| Message ID | 20110125021652.GA21397@intel.com |
|---|---|
| State | New |
| Headers | show |
On 01/25/2011 03:16 AM, H.J. Lu wrote: > Hi, > > fwprop propagates zero/sign extended hard registers while not propagating > hard registers in propagate_rtx. This patch avoids propagating zero/sign > extended hard registers. OK for 4.7? Is this a regression from say 3.4 or 4.1? The patch surely fixes a thinko, and the same ought to be done in forward_propagate_subreg too. fwprop isn't meant to deal with hard registers, especially on SMALL_REGISTER_CLASSES machine its transforms are the exact opposite of what you ought to do... Paolo
On Mon, Jan 24, 2011 at 7:02 PM, Paolo Bonzini <bonzini@gnu.org> wrote: > On 01/25/2011 03:16 AM, H.J. Lu wrote: >> >> Hi, >> >> fwprop propagates zero/sign extended hard registers while not propagating >> hard registers in propagate_rtx. This patch avoids propagating zero/sign >> extended hard registers. OK for 4.7? > > Is this a regression from say 3.4 or 4.1? The patch surely fixes a thinko, > and the same ought to be done in forward_propagate_subreg too. This is a regression from gcc 4.4 since propagating zero/sign extended hard registers was added to gcc 4.5: http://gcc.gnu.org/ml/gcc-cvs/2009-08/msg00704.html > fwprop isn't meant to deal with hard registers, especially on > SMALL_REGISTER_CLASSES machine its transforms are the exact opposite of what > you ought to do... > There are also: /* If this is a paradoxical SUBREG... */ if (GET_MODE_SIZE (use_mode) > GET_MODE_SIZE (GET_MODE (SUBREG_REG (use_reg)))) { /* If this is a paradoxical SUBREG, we have no idea what value the extra bits would have. However, if the operand is equivalent to a SUBREG whose operand is the same as our mode, and all the modes are within a word, we can just use the inner operand because these SUBREGs just say how to treat the register. */ use_insn = DF_REF_INSN (use); src = SET_SRC (def_set); if (GET_CODE (src) == SUBREG && REG_P (SUBREG_REG (src)) && GET_MODE (SUBREG_REG (src)) == use_mode && subreg_lowpart_p (src) && all_uses_available_at (def_insn, use_insn)) return try_fwprop_subst (use, DF_REF_LOC (use), SUBREG_REG (src), def_insn, false); } Should it check hard registers?
On 01/25/2011 04:50 AM, H.J. Lu wrote: > /* If this is a paradoxical SUBREG... */ > if (GET_MODE_SIZE (use_mode) > > GET_MODE_SIZE (GET_MODE (SUBREG_REG (use_reg)))) > { > /* If this is a paradoxical SUBREG, we have no idea what value the > extra bits would have. However, if the operand is equivalent to > a SUBREG whose operand is the same as our mode, and all the modes > are within a word, we can just use the inner operand because > these SUBREGs just say how to treat the register. */ > use_insn = DF_REF_INSN (use); > src = SET_SRC (def_set); > if (GET_CODE (src) == SUBREG > && REG_P (SUBREG_REG (src)) > && GET_MODE (SUBREG_REG (src)) == use_mode > && subreg_lowpart_p (src) > && all_uses_available_at (def_insn, use_insn)) > return try_fwprop_subst (use, DF_REF_LOC (use), SUBREG_REG (src), > def_insn, false); > } > > Should it check hard registers? Yes. Paolo
diff --git a/gcc/ChangeLog.x32 b/gcc/ChangeLog.x32 index ebe1d13..761799f 100644 --- a/gcc/ChangeLog.x32 +++ b/gcc/ChangeLog.x32 @@ -1,5 +1,11 @@ 2011-01-24 H.J. Lu <hongjiu.lu@intel.com> + PR middle-end/47449 + * fwprop.c (forward_propagate_subreg): Don't propagate zero/sign + extended hard register. + +2011-01-24 H.J. Lu <hongjiu.lu@intel.com> + PR target/47446 * config/i386/i386.c (ix86_output_addr_vec_elt): Check TARGET_LP64 instead of TARGET_64BIT for ASM_QUAD. diff --git a/gcc/fwprop.c b/gcc/fwprop.c index 7ff5135..866cbe3 100644 --- a/gcc/fwprop.c +++ b/gcc/fwprop.c @@ -1119,6 +1119,7 @@ forward_propagate_subreg (df_ref use, rtx def_insn, rtx def_set) if ((GET_CODE (src) == ZERO_EXTEND || GET_CODE (src) == SIGN_EXTEND) && REG_P (XEXP (src, 0)) + && REGNO (XEXP (src, 0)) >= FIRST_PSEUDO_REGISTER && GET_MODE (XEXP (src, 0)) == use_mode && !free_load_extend (src, def_insn) && all_uses_available_at (def_insn, use_insn)) diff --git a/gcc/testsuite/ChangeLog.x32 b/gcc/testsuite/ChangeLog.x32 index 506585d..271a2ae 100644 --- a/gcc/testsuite/ChangeLog.x32 +++ b/gcc/testsuite/ChangeLog.x32 @@ -1,5 +1,10 @@ 2011-01-24 H.J. Lu <hongjiu.lu@intel.com> + PR middle-end/47449 + * gcc.target/i386/pr47449.c: New. + +2011-01-24 H.J. Lu <hongjiu.lu@intel.com> + PR target/47446 * gcc.target/i386/pr47446-1.c: New. diff --git a/gcc/testsuite/gcc.target/i386/pr47449.c b/gcc/testsuite/gcc.target/i386/pr47449.c new file mode 100644 index 0000000..99ef32f --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr47449.c @@ -0,0 +1,12 @@ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +void bar (void *, void *); +int +foo (void *p1, void *p2) +{ + int ret1, ret2; + __asm ("" : "=D" (ret1), "=S" (ret2)); + bar (p1, p2); + return ret1 + ret2; +}
Hi, fwprop propagates zero/sign extended hard registers while not propagating hard registers in propagate_rtx. This patch avoids propagating zero/sign extended hard registers. OK for 4.7? Thanks. H.J. --- commit 9fe3f4242e370b5728223e4198eb34b82eaa7e33 Author: H.J. Lu <hjl.tools@gmail.com> Date: Mon Jan 24 18:11:35 2011 -0800 Don't propagate zero/sign extended hard register.