| Message ID | b3691025-50e7-433f-9fa9-0c997e19479d@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | [RFC] combine: Don't truncate const operand of AND if it's no benefits | expand |
Hi, Gently ping this: https://gcc.gnu.org/pipermail/gcc-patches/2024-March/647533.html Thanks Gui Haochen 在 2024/3/11 13:41, HAO CHEN GUI 写道: > Hi, > This patch tries to fix the problem when a canonical form doesn't benefit > on a specific target. The const operand of AND is and with the nonzero > bits of another operand in combine pass. It's a canonical form, but it's no > benefits for the target which has rotate and mask insns. As the mask is > truncated, it can't match the insn conditions which it originally matches. > For example, the following insn condition checks the sum of two AND masks. > When one of the mask is truncated, the condition breaks. > > (define_insn "*rotlsi3_insert_5" > [(set (match_operand:SI 0 "gpc_reg_operand" "=r,r") > (ior:SI (and:SI (match_operand:SI 1 "gpc_reg_operand" "0,r") > (match_operand:SI 2 "const_int_operand" "n,n")) > (and:SI (match_operand:SI 3 "gpc_reg_operand" "r,0") > (match_operand:SI 4 "const_int_operand" "n,n"))))] > "rs6000_is_valid_mask (operands[2], NULL, NULL, SImode) > && UINTVAL (operands[2]) != 0 && UINTVAL (operands[4]) != 0 > && UINTVAL (operands[2]) + UINTVAL (operands[4]) + 1 == 0" > ... > > This patch tries to fix the problem by comparing the rtx cost. If another > operand (varop) is not changed and rtx cost with new mask is not less than > the original one, the mask is restored to original one. > > I'm not sure if comparison of rtx cost here is proper. The outer code is > unknown and I suppose it as "SET". Also the rtx cost might not be accurate. > From my understanding, the canonical forms should always benefit as it can't > be undo in combine pass. Do we have a perfect solution for this kind of > issues? Looking forward for your advice. > > Another similar issues for canonical forms. Whether the widen mode for > lshiftrt is always good? > https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624852.html > > Thanks > Gui Haochen > > ChangeLog > Combine: Don't truncate const operand of AND if it's no benefits > > In combine pass, the canonical form is to turn off all bits in the constant > that are know to already be zero for AND. > > /* Turn off all bits in the constant that are known to already be zero. > Thus, if the AND isn't needed at all, we will have CONSTOP == NONZERO_BITS > which is tested below. */ > > constop &= nonzero; > > But it doesn't benefit when the target has rotate and mask insert insns. > The AND mask is truncated and lost its information. Thus it can't match > the insn conditions. For example, the following insn condition checks > the sum of two AND masks. > > (define_insn "*rotlsi3_insert_5" > [(set (match_operand:SI 0 "gpc_reg_operand" "=r,r") > (ior:SI (and:SI (match_operand:SI 1 "gpc_reg_operand" "0,r") > (match_operand:SI 2 "const_int_operand" "n,n")) > (and:SI (match_operand:SI 3 "gpc_reg_operand" "r,0") > (match_operand:SI 4 "const_int_operand" "n,n"))))] > "rs6000_is_valid_mask (operands[2], NULL, NULL, SImode) > && UINTVAL (operands[2]) != 0 && UINTVAL (operands[4]) != 0 > && UINTVAL (operands[2]) + UINTVAL (operands[4]) + 1 == 0" > ... > > This patch restores the const operand of AND if the another operand is > not optimized and the truncated const operand doesn't save the rtx cost. > > gcc/ > * combine.cc (simplify_and_const_int_1): Restore the const operand > of AND if varop is not optimized and the rtx cost of the new const > operand is not reduced. > > gcc/testsuite/ > * gcc.target/powerpc/rlwimi-0.c: Reduced total number of insns and > adjust the number of rotate and mask insns. > * gcc.target/powerpc/rlwimi-1.c: Likewise. > * gcc.target/powerpc/rlwimi-2.c: Likewise. > > patch.diff > diff --git a/gcc/combine.cc b/gcc/combine.cc > index a4479f8d836..16ff09ea854 100644 > --- a/gcc/combine.cc > +++ b/gcc/combine.cc > @@ -10161,8 +10161,23 @@ simplify_and_const_int_1 (scalar_int_mode mode, rtx varop, > if (constop == nonzero) > return varop; > > - if (varop == orig_varop && constop == orig_constop) > - return NULL_RTX; > + if (varop == orig_varop) > + { > + if (constop == orig_constop) > + return NULL_RTX; > + else > + { > + rtx tmp = simplify_gen_binary (AND, mode, varop, > + gen_int_mode (constop, mode)); > + rtx orig = simplify_gen_binary (AND, mode, varop, > + gen_int_mode (orig_constop, mode)); > + if (set_src_cost (tmp, mode, optimize_this_for_speed_p) > + < set_src_cost (orig, mode, optimize_this_for_speed_p)) > + return tmp; > + else > + return NULL_RTX; > + } > + } > > /* Otherwise, return an AND. */ > return simplify_gen_binary (AND, mode, varop, gen_int_mode (constop, mode)); > diff --git a/gcc/testsuite/gcc.target/powerpc/rlwimi-0.c b/gcc/testsuite/gcc.target/powerpc/rlwimi-0.c > index 961be199901..d9dd4419f1d 100644 > --- a/gcc/testsuite/gcc.target/powerpc/rlwimi-0.c > +++ b/gcc/testsuite/gcc.target/powerpc/rlwimi-0.c > @@ -2,15 +2,15 @@ > /* { dg-options "-O2" } */ > > /* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 16485 { target ilp32 } } } */ > -/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 19909 { target lp64 } } } */ > +/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 19780 { target lp64 } } } */ > /* { dg-final { scan-assembler-times {(?n)^\s+blr} 6750 } } */ > /* { dg-final { scan-assembler-times {(?n)^\s+mr} 3007 { target ilp32 } } } */ > -/* { dg-final { scan-assembler-times {(?n)^\s+mr} 11 { target lp64 } } } */ > -/* { dg-final { scan-assembler-times {(?n)^\s+rldicl} 6420 { target lp64 } } } */ > +/* { dg-final { scan-assembler-times {(?n)^\s+mr} 140 { target lp64 } } } */ > +/* { dg-final { scan-assembler-times {(?n)^\s+rldicl} 6162 { target lp64 } } } */ > > /* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 6420 { target ilp32 } } } */ > -/* { dg-final { scan-assembler-times {(?n)^\s+rldimi} 310 { target lp64 } } } */ > -/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 6110 { target lp64 } } } */ > +/* { dg-final { scan-assembler-times {(?n)^\s+rldimi} 366 { target lp64 } } } */ > +/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 6054 { target lp64 } } } */ > /* { dg-final { scan-assembler-times {(?n)^\s+rotlwi} 308 } } */ > > > diff --git a/gcc/testsuite/gcc.target/powerpc/rlwimi-1.c b/gcc/testsuite/gcc.target/powerpc/rlwimi-1.c > index e2c607b1d45..d955fc792d9 100644 > --- a/gcc/testsuite/gcc.target/powerpc/rlwimi-1.c > +++ b/gcc/testsuite/gcc.target/powerpc/rlwimi-1.c > @@ -2,15 +2,15 @@ > /* { dg-options "-O2" } */ > > /* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 13977 { target ilp32 } } } */ > -/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 20217 { target lp64 } } } */ > +/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 20189 { target lp64 } } } */ > /* { dg-final { scan-assembler-times {(?n)^\s+blr} 6750 } } */ > /* { dg-final { scan-assembler-times {(?n)^\s+mr} 499 { target ilp32 } } } */ > -/* { dg-final { scan-assembler-times {(?n)^\s+mr} 11 { target lp64 } } } */ > -/* { dg-final { scan-assembler-times {(?n)^\s+rldicl} 6728 { target lp64 } } } */ > +/* { dg-final { scan-assembler-times {(?n)^\s+mr} 39 { target lp64 } } } */ > +/* { dg-final { scan-assembler-times {(?n)^\s+rldicl} 6672 { target lp64 } } } */ > > /* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1404 { target ilp32 } } } */ > -/* { dg-final { scan-assembler-times {(?n)^\s+rldimi} 134 { target lp64 } } } */ > -/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1270 { target lp64 } } } */ > +/* { dg-final { scan-assembler-times {(?n)^\s+rldimi} 190 { target lp64 } } } */ > +/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1214 { target lp64 } } } */ > > /* { dg-final { scan-assembler-times {(?n)^\s+mulli} 5324 } } */ > > diff --git a/gcc/testsuite/gcc.target/powerpc/rlwimi-2.c b/gcc/testsuite/gcc.target/powerpc/rlwimi-2.c > index bafa371db73..9abfd7abf08 100644 > --- a/gcc/testsuite/gcc.target/powerpc/rlwimi-2.c > +++ b/gcc/testsuite/gcc.target/powerpc/rlwimi-2.c > @@ -2,14 +2,14 @@ > /* { dg-options "-O2" } */ > > /* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 14121 { target ilp32 } } } */ > -/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 20217 { target lp64 } } } */ > +/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 19622 { target lp64 } } } */ > /* { dg-final { scan-assembler-times {(?n)^\s+blr} 6750 } } */ > /* { dg-final { scan-assembler-times {(?n)^\s+mr} 643 { target ilp32 } } } */ > -/* { dg-final { scan-assembler-times {(?n)^\s+mr} 11 { target lp64 } } } */ > -/* { dg-final { scan-assembler-times {(?n)^\s+rldicl} 7790 { target lp64 } } } */ > +/* { dg-final { scan-assembler-times {(?n)^\s+mr} 658 { target lp64 } } } */ > +/* { dg-final { scan-assembler-times {(?n)^\s+rldicl} 5460 { target lp64 } } } */ > > /* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1692 { target ilp32 } } } */ > -/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1666 { target lp64 } } } */ > +/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1610 { target lp64 } } } */ > > /* { dg-final { scan-assembler-times {(?n)^\s+mulli} 5036 } } */ >
On 3/10/24 11:41 PM, HAO CHEN GUI wrote: > Hi, > This patch tries to fix the problem when a canonical form doesn't benefit > on a specific target. The const operand of AND is and with the nonzero > bits of another operand in combine pass. It's a canonical form, but it's no > benefits for the target which has rotate and mask insns. As the mask is > truncated, it can't match the insn conditions which it originally matches. > For example, the following insn condition checks the sum of two AND masks. > When one of the mask is truncated, the condition breaks. > > (define_insn "*rotlsi3_insert_5" > [(set (match_operand:SI 0 "gpc_reg_operand" "=r,r") > (ior:SI (and:SI (match_operand:SI 1 "gpc_reg_operand" "0,r") > (match_operand:SI 2 "const_int_operand" "n,n")) > (and:SI (match_operand:SI 3 "gpc_reg_operand" "r,0") > (match_operand:SI 4 "const_int_operand" "n,n"))))] > "rs6000_is_valid_mask (operands[2], NULL, NULL, SImode) > && UINTVAL (operands[2]) != 0 && UINTVAL (operands[4]) != 0 > && UINTVAL (operands[2]) + UINTVAL (operands[4]) + 1 == 0" > ... > > This patch tries to fix the problem by comparing the rtx cost. If another > operand (varop) is not changed and rtx cost with new mask is not less than > the original one, the mask is restored to original one. > > I'm not sure if comparison of rtx cost here is proper. The outer code is > unknown and I suppose it as "SET". Also the rtx cost might not be accurate. > From my understanding, the canonical forms should always benefit as it can't > be undo in combine pass. Do we have a perfect solution for this kind of > issues? Looking forward for your advice. > > Another similar issues for canonical forms. Whether the widen mode for > lshiftrt is always good? > https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624852.html > > Thanks > Gui Haochen > > ChangeLog > Combine: Don't truncate const operand of AND if it's no benefits > > In combine pass, the canonical form is to turn off all bits in the constant > that are know to already be zero for AND. > > /* Turn off all bits in the constant that are known to already be zero. > Thus, if the AND isn't needed at all, we will have CONSTOP == NONZERO_BITS > which is tested below. */ > > constop &= nonzero; > > But it doesn't benefit when the target has rotate and mask insert insns. > The AND mask is truncated and lost its information. Thus it can't match > the insn conditions. For example, the following insn condition checks > the sum of two AND masks. > > (define_insn "*rotlsi3_insert_5" > [(set (match_operand:SI 0 "gpc_reg_operand" "=r,r") > (ior:SI (and:SI (match_operand:SI 1 "gpc_reg_operand" "0,r") > (match_operand:SI 2 "const_int_operand" "n,n")) > (and:SI (match_operand:SI 3 "gpc_reg_operand" "r,0") > (match_operand:SI 4 "const_int_operand" "n,n"))))] > "rs6000_is_valid_mask (operands[2], NULL, NULL, SImode) > && UINTVAL (operands[2]) != 0 && UINTVAL (operands[4]) != 0 > && UINTVAL (operands[2]) + UINTVAL (operands[4]) + 1 == 0" > ... > > This patch restores the const operand of AND if the another operand is > not optimized and the truncated const operand doesn't save the rtx cost. > > gcc/ > * combine.cc (simplify_and_const_int_1): Restore the const operand > of AND if varop is not optimized and the rtx cost of the new const > operand is not reduced. > > gcc/testsuite/ > * gcc.target/powerpc/rlwimi-0.c: Reduced total number of insns and > adjust the number of rotate and mask insns. > * gcc.target/powerpc/rlwimi-1.c: Likewise. > * gcc.target/powerpc/rlwimi-2.c: Likewise. It seems like this should defer to gcc-15. jeff
diff --git a/gcc/combine.cc b/gcc/combine.cc index a4479f8d836..16ff09ea854 100644 --- a/gcc/combine.cc +++ b/gcc/combine.cc @@ -10161,8 +10161,23 @@ simplify_and_const_int_1 (scalar_int_mode mode, rtx varop, if (constop == nonzero) return varop; - if (varop == orig_varop && constop == orig_constop) - return NULL_RTX; + if (varop == orig_varop) + { + if (constop == orig_constop) + return NULL_RTX; + else + { + rtx tmp = simplify_gen_binary (AND, mode, varop, + gen_int_mode (constop, mode)); + rtx orig = simplify_gen_binary (AND, mode, varop, + gen_int_mode (orig_constop, mode)); + if (set_src_cost (tmp, mode, optimize_this_for_speed_p) + < set_src_cost (orig, mode, optimize_this_for_speed_p)) + return tmp; + else + return NULL_RTX; + } + } /* Otherwise, return an AND. */ return simplify_gen_binary (AND, mode, varop, gen_int_mode (constop, mode)); diff --git a/gcc/testsuite/gcc.target/powerpc/rlwimi-0.c b/gcc/testsuite/gcc.target/powerpc/rlwimi-0.c index 961be199901..d9dd4419f1d 100644 --- a/gcc/testsuite/gcc.target/powerpc/rlwimi-0.c +++ b/gcc/testsuite/gcc.target/powerpc/rlwimi-0.c @@ -2,15 +2,15 @@ /* { dg-options "-O2" } */ /* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 16485 { target ilp32 } } } */ -/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 19909 { target lp64 } } } */ +/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 19780 { target lp64 } } } */ /* { dg-final { scan-assembler-times {(?n)^\s+blr} 6750 } } */ /* { dg-final { scan-assembler-times {(?n)^\s+mr} 3007 { target ilp32 } } } */ -/* { dg-final { scan-assembler-times {(?n)^\s+mr} 11 { target lp64 } } } */ -/* { dg-final { scan-assembler-times {(?n)^\s+rldicl} 6420 { target lp64 } } } */ +/* { dg-final { scan-assembler-times {(?n)^\s+mr} 140 { target lp64 } } } */ +/* { dg-final { scan-assembler-times {(?n)^\s+rldicl} 6162 { target lp64 } } } */ /* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 6420 { target ilp32 } } } */ -/* { dg-final { scan-assembler-times {(?n)^\s+rldimi} 310 { target lp64 } } } */ -/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 6110 { target lp64 } } } */ +/* { dg-final { scan-assembler-times {(?n)^\s+rldimi} 366 { target lp64 } } } */ +/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 6054 { target lp64 } } } */ /* { dg-final { scan-assembler-times {(?n)^\s+rotlwi} 308 } } */ diff --git a/gcc/testsuite/gcc.target/powerpc/rlwimi-1.c b/gcc/testsuite/gcc.target/powerpc/rlwimi-1.c index e2c607b1d45..d955fc792d9 100644 --- a/gcc/testsuite/gcc.target/powerpc/rlwimi-1.c +++ b/gcc/testsuite/gcc.target/powerpc/rlwimi-1.c @@ -2,15 +2,15 @@ /* { dg-options "-O2" } */ /* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 13977 { target ilp32 } } } */ -/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 20217 { target lp64 } } } */ +/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 20189 { target lp64 } } } */ /* { dg-final { scan-assembler-times {(?n)^\s+blr} 6750 } } */ /* { dg-final { scan-assembler-times {(?n)^\s+mr} 499 { target ilp32 } } } */ -/* { dg-final { scan-assembler-times {(?n)^\s+mr} 11 { target lp64 } } } */ -/* { dg-final { scan-assembler-times {(?n)^\s+rldicl} 6728 { target lp64 } } } */ +/* { dg-final { scan-assembler-times {(?n)^\s+mr} 39 { target lp64 } } } */ +/* { dg-final { scan-assembler-times {(?n)^\s+rldicl} 6672 { target lp64 } } } */ /* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1404 { target ilp32 } } } */ -/* { dg-final { scan-assembler-times {(?n)^\s+rldimi} 134 { target lp64 } } } */ -/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1270 { target lp64 } } } */ +/* { dg-final { scan-assembler-times {(?n)^\s+rldimi} 190 { target lp64 } } } */ +/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1214 { target lp64 } } } */ /* { dg-final { scan-assembler-times {(?n)^\s+mulli} 5324 } } */ diff --git a/gcc/testsuite/gcc.target/powerpc/rlwimi-2.c b/gcc/testsuite/gcc.target/powerpc/rlwimi-2.c index bafa371db73..9abfd7abf08 100644 --- a/gcc/testsuite/gcc.target/powerpc/rlwimi-2.c +++ b/gcc/testsuite/gcc.target/powerpc/rlwimi-2.c @@ -2,14 +2,14 @@ /* { dg-options "-O2" } */ /* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 14121 { target ilp32 } } } */ -/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 20217 { target lp64 } } } */ +/* { dg-final { scan-assembler-times {(?n)^\s+[a-z]} 19622 { target lp64 } } } */ /* { dg-final { scan-assembler-times {(?n)^\s+blr} 6750 } } */ /* { dg-final { scan-assembler-times {(?n)^\s+mr} 643 { target ilp32 } } } */ -/* { dg-final { scan-assembler-times {(?n)^\s+mr} 11 { target lp64 } } } */ -/* { dg-final { scan-assembler-times {(?n)^\s+rldicl} 7790 { target lp64 } } } */ +/* { dg-final { scan-assembler-times {(?n)^\s+mr} 658 { target lp64 } } } */ +/* { dg-final { scan-assembler-times {(?n)^\s+rldicl} 5460 { target lp64 } } } */ /* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1692 { target ilp32 } } } */ -/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1666 { target lp64 } } } */ +/* { dg-final { scan-assembler-times {(?n)^\s+rlwimi} 1610 { target lp64 } } } */ /* { dg-final { scan-assembler-times {(?n)^\s+mulli} 5036 } } */
Hi, This patch tries to fix the problem when a canonical form doesn't benefit on a specific target. The const operand of AND is and with the nonzero bits of another operand in combine pass. It's a canonical form, but it's no benefits for the target which has rotate and mask insns. As the mask is truncated, it can't match the insn conditions which it originally matches. For example, the following insn condition checks the sum of two AND masks. When one of the mask is truncated, the condition breaks. (define_insn "*rotlsi3_insert_5" [(set (match_operand:SI 0 "gpc_reg_operand" "=r,r") (ior:SI (and:SI (match_operand:SI 1 "gpc_reg_operand" "0,r") (match_operand:SI 2 "const_int_operand" "n,n")) (and:SI (match_operand:SI 3 "gpc_reg_operand" "r,0") (match_operand:SI 4 "const_int_operand" "n,n"))))] "rs6000_is_valid_mask (operands[2], NULL, NULL, SImode) && UINTVAL (operands[2]) != 0 && UINTVAL (operands[4]) != 0 && UINTVAL (operands[2]) + UINTVAL (operands[4]) + 1 == 0" ... This patch tries to fix the problem by comparing the rtx cost. If another operand (varop) is not changed and rtx cost with new mask is not less than the original one, the mask is restored to original one. I'm not sure if comparison of rtx cost here is proper. The outer code is unknown and I suppose it as "SET". Also the rtx cost might not be accurate. From my understanding, the canonical forms should always benefit as it can't be undo in combine pass. Do we have a perfect solution for this kind of issues? Looking forward for your advice. Another similar issues for canonical forms. Whether the widen mode for lshiftrt is always good? https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624852.html Thanks Gui Haochen ChangeLog Combine: Don't truncate const operand of AND if it's no benefits In combine pass, the canonical form is to turn off all bits in the constant that are know to already be zero for AND. /* Turn off all bits in the constant that are known to already be zero. Thus, if the AND isn't needed at all, we will have CONSTOP == NONZERO_BITS which is tested below. */ constop &= nonzero; But it doesn't benefit when the target has rotate and mask insert insns. The AND mask is truncated and lost its information. Thus it can't match the insn conditions. For example, the following insn condition checks the sum of two AND masks. (define_insn "*rotlsi3_insert_5" [(set (match_operand:SI 0 "gpc_reg_operand" "=r,r") (ior:SI (and:SI (match_operand:SI 1 "gpc_reg_operand" "0,r") (match_operand:SI 2 "const_int_operand" "n,n")) (and:SI (match_operand:SI 3 "gpc_reg_operand" "r,0") (match_operand:SI 4 "const_int_operand" "n,n"))))] "rs6000_is_valid_mask (operands[2], NULL, NULL, SImode) && UINTVAL (operands[2]) != 0 && UINTVAL (operands[4]) != 0 && UINTVAL (operands[2]) + UINTVAL (operands[4]) + 1 == 0" ... This patch restores the const operand of AND if the another operand is not optimized and the truncated const operand doesn't save the rtx cost. gcc/ * combine.cc (simplify_and_const_int_1): Restore the const operand of AND if varop is not optimized and the rtx cost of the new const operand is not reduced. gcc/testsuite/ * gcc.target/powerpc/rlwimi-0.c: Reduced total number of insns and adjust the number of rotate and mask insns. * gcc.target/powerpc/rlwimi-1.c: Likewise. * gcc.target/powerpc/rlwimi-2.c: Likewise. patch.diff