| Message ID | CAFULd4ZJ4BKDUSee=PjQc892pDg1uxR+XsUbG4Lw38xi_oBd5Q@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
On 09/04/2016 02:12 PM, Uros Bizjak wrote: > As shown in the PR [1], combine is able to simplify lowpart > CONST_VECTOR constant pool reference to its inner-mode reference. > However, plus_constant was not able to extract the constant from > narrowed access. > > Attached patch teaches plus_constant how to handle this situation. Ok. It looks like accesses to non-lowpart subregs would be handled by not optimizing them as well rather than crashing. Bernd
On September 5, 2016 12:11:47 PM GMT+02:00, Bernd Schmidt <bschmidt@redhat.com> wrote: >On 09/04/2016 02:12 PM, Uros Bizjak wrote: >> As shown in the PR [1], combine is able to simplify lowpart >> CONST_VECTOR constant pool reference to its inner-mode reference. >> However, plus_constant was not able to extract the constant from >> narrowed access. >> >> Attached patch teaches plus_constant how to handle this situation. > >Ok. It looks like accesses to non-lowpart subregs would be handled by >not optimizing them as well rather than crashing. Are we missing similar handling for complex integer constants? Richard. > >Bernd
Index: explow.c =================================================================== --- explow.c (revision 239975) +++ explow.c (working copy) @@ -106,7 +106,15 @@ plus_constant (machine_mode mode, rtx x, HOST_WIDE if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0))) { - tem = plus_constant (mode, get_pool_constant (XEXP (x, 0)), c); + rtx cst = get_pool_constant (XEXP (x, 0)); + + if (GET_CODE (cst) == CONST_VECTOR + && GET_MODE_INNER (GET_MODE (cst)) == mode) + { + cst = gen_lowpart (mode, cst); + gcc_assert (cst); + } + tem = plus_constant (mode, cst, c); tem = force_const_mem (GET_MODE (x), tem); /* Targets may disallow some constants in the constant pool, thus force_const_mem may return NULL_RTX. */ Index: testsuite/gcc.target/i386/pr77452.c =================================================================== --- testsuite/gcc.target/i386/pr77452.c (nonexistent) +++ testsuite/gcc.target/i386/pr77452.c (working copy) @@ -0,0 +1,13 @@ +/* { dg-do compile { target int128 } } */ +/* { dg-options "-O -mavx512f -fno-split-wide-types --param max-combine-insns=2" } */ + +typedef unsigned int U __attribute__((vector_size(64))); +typedef unsigned __int128 V __attribute__((vector_size(64))); + +V +foo(V v) +{ + v[0] = 1u << (( ((V)(U){1, 1, v[0]})[0]) & 0xf) + >> ((-~((V)(U){1, 1, v[0]})[0]) & 0xf); + return v; +}
Hello! As shown in the PR [1], combine is able to simplify lowpart CONST_VECTOR constant pool reference to its inner-mode reference. However, plus_constant was not able to extract the constant from narrowed access. Attached patch teaches plus_constant how to handle this situation. 2016-09-04 Uros Bizjak <ubizjak@gmail.com> PR rtl-optimization/77452 * explow.c (plus_constant) <case MEM>: Extract scalar constant from inner-mode reference to a CONST_VECTOR constant in the constant pool. 2016-09-04 Uros Bizjak <ubizjak@gmail.com> testsuite/ChangeLog: PR rtl-optimization/77452 * gcc.target/i386/pr77452.c: New test. Patch was bootstrapped and regression tested on x86_64-linux-gnu {,-m32}. OK for mainline and gcc-6 branch? [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77452 Uros.