From: Stefan Schulze Frielinghaus Date: Wed, 2 Aug 2023 19:43:22 +0000 (+0200) Subject: rtl-optimization/110867 Fix narrow comparison of memory and constant X-Git-Tag: basepoints/gcc-15~7207 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=41ef5a34161356817807be3a2e51fbdbe575ae85;p=thirdparty%2Fgcc.git rtl-optimization/110867 Fix narrow comparison of memory and constant In certain cases a constant may not fit into the mode used to perform a comparison. This may be the case for sign-extended constants which are used during an unsigned comparison as e.g. in (set (reg:CC 100 cc) (compare:CC (mem:SI (reg/v/f:SI 115 [ a ]) [1 *a_4(D)+0 S4 A64]) (const_int -2147483648 [0xffffffff80000000]))) Fixed by ensuring that the constant fits into comparison mode. Furthermore, on some targets as e.g. sparc the constant used in a comparison is chopped off before combine which leads to failing test cases (see PR 110869). Fixed by not requiring that the source mode has to be DImode, and excluding sparc from the last two test cases entirely since there the constant cannot be further reduced. gcc/ChangeLog: PR rtl-optimization/110867 * combine.cc (simplify_compare_const): Try the optimization only in case the constant fits into the comparison mode. gcc/testsuite/ChangeLog: PR rtl-optimization/110869 * gcc.dg/cmp-mem-const-1.c: Relax mode for constant. * gcc.dg/cmp-mem-const-2.c: Relax mode for constant. * gcc.dg/cmp-mem-const-3.c: Relax mode for constant. * gcc.dg/cmp-mem-const-4.c: Relax mode for constant. * gcc.dg/cmp-mem-const-5.c: Exclude sparc since here the constant is already reduced. * gcc.dg/cmp-mem-const-6.c: Exclude sparc since here the constant is already reduced. --- diff --git a/gcc/combine.cc b/gcc/combine.cc index 0d99fa541c5a..e46d202d0a7e 100644 --- a/gcc/combine.cc +++ b/gcc/combine.cc @@ -11998,11 +11998,15 @@ simplify_compare_const (enum rtx_code code, machine_mode mode, x0 >= 0x40. */ if ((code == LEU || code == LTU || code == GEU || code == GTU) && is_a (GET_MODE (op0), &int_mode) + && HWI_COMPUTABLE_MODE_P (int_mode) && MEM_P (op0) && !MEM_VOLATILE_P (op0) /* The optimization makes only sense for constants which are big enough so that we have a chance to chop off something at all. */ && (unsigned HOST_WIDE_INT) const_op > 0xff + /* Bail out, if the constant does not fit into INT_MODE. */ + && (unsigned HOST_WIDE_INT) const_op + < ((HOST_WIDE_INT_1U << (GET_MODE_PRECISION (int_mode) - 1) << 1) - 1) /* Ensure that we do not overflow during normalization. */ && (code != GTU || (unsigned HOST_WIDE_INT) const_op < HOST_WIDE_INT_M1U)) { diff --git a/gcc/testsuite/gcc.dg/cmp-mem-const-1.c b/gcc/testsuite/gcc.dg/cmp-mem-const-1.c index 263ad98af79d..4f21a1ade4a3 100644 --- a/gcc/testsuite/gcc.dg/cmp-mem-const-1.c +++ b/gcc/testsuite/gcc.dg/cmp-mem-const-1.c @@ -1,6 +1,6 @@ /* { dg-do compile { target { lp64 } } } */ /* { dg-options "-O1 -fdump-rtl-combine-details" } */ -/* { dg-final { scan-rtl-dump "narrow comparison from mode DI to QI" "combine" } } */ +/* { dg-final { scan-rtl-dump "narrow comparison from mode .I to QI" "combine" } } */ typedef __UINT64_TYPE__ uint64_t; diff --git a/gcc/testsuite/gcc.dg/cmp-mem-const-2.c b/gcc/testsuite/gcc.dg/cmp-mem-const-2.c index a7cc5348295c..7b722951594c 100644 --- a/gcc/testsuite/gcc.dg/cmp-mem-const-2.c +++ b/gcc/testsuite/gcc.dg/cmp-mem-const-2.c @@ -1,6 +1,6 @@ /* { dg-do compile { target { lp64 } } } */ /* { dg-options "-O1 -fdump-rtl-combine-details" } */ -/* { dg-final { scan-rtl-dump "narrow comparison from mode DI to QI" "combine" } } */ +/* { dg-final { scan-rtl-dump "narrow comparison from mode .I to QI" "combine" } } */ typedef __UINT64_TYPE__ uint64_t; diff --git a/gcc/testsuite/gcc.dg/cmp-mem-const-3.c b/gcc/testsuite/gcc.dg/cmp-mem-const-3.c index 06f80bf72d8e..ed5059d38074 100644 --- a/gcc/testsuite/gcc.dg/cmp-mem-const-3.c +++ b/gcc/testsuite/gcc.dg/cmp-mem-const-3.c @@ -1,6 +1,6 @@ /* { dg-do compile { target { lp64 } } } */ /* { dg-options "-O1 -fdump-rtl-combine-details" } */ -/* { dg-final { scan-rtl-dump "narrow comparison from mode DI to HI" "combine" } } */ +/* { dg-final { scan-rtl-dump "narrow comparison from mode .I to HI" "combine" } } */ typedef __UINT64_TYPE__ uint64_t; diff --git a/gcc/testsuite/gcc.dg/cmp-mem-const-4.c b/gcc/testsuite/gcc.dg/cmp-mem-const-4.c index 407999abf7e9..23e83372beed 100644 --- a/gcc/testsuite/gcc.dg/cmp-mem-const-4.c +++ b/gcc/testsuite/gcc.dg/cmp-mem-const-4.c @@ -1,6 +1,6 @@ /* { dg-do compile { target { lp64 } } } */ /* { dg-options "-O1 -fdump-rtl-combine-details" } */ -/* { dg-final { scan-rtl-dump "narrow comparison from mode DI to HI" "combine" } } */ +/* { dg-final { scan-rtl-dump "narrow comparison from mode .I to HI" "combine" } } */ typedef __UINT64_TYPE__ uint64_t; diff --git a/gcc/testsuite/gcc.dg/cmp-mem-const-5.c b/gcc/testsuite/gcc.dg/cmp-mem-const-5.c index e16773f5bcf1..d266896a25e0 100644 --- a/gcc/testsuite/gcc.dg/cmp-mem-const-5.c +++ b/gcc/testsuite/gcc.dg/cmp-mem-const-5.c @@ -1,6 +1,6 @@ -/* { dg-do compile { target { lp64 } } } */ +/* { dg-do compile { target { lp64 } && ! target { sparc*-*-* } } } */ /* { dg-options "-O1 -fdump-rtl-combine-details" } */ -/* { dg-final { scan-rtl-dump "narrow comparison from mode DI to SI" "combine" } } */ +/* { dg-final { scan-rtl-dump "narrow comparison from mode .I to SI" "combine" } } */ typedef __UINT64_TYPE__ uint64_t; diff --git a/gcc/testsuite/gcc.dg/cmp-mem-const-6.c b/gcc/testsuite/gcc.dg/cmp-mem-const-6.c index 8f53b5678bd8..68d7a9d02658 100644 --- a/gcc/testsuite/gcc.dg/cmp-mem-const-6.c +++ b/gcc/testsuite/gcc.dg/cmp-mem-const-6.c @@ -1,6 +1,6 @@ -/* { dg-do compile { target { lp64 } } } */ +/* { dg-do compile { target { lp64 } && ! target { sparc*-*-* } } } */ /* { dg-options "-O1 -fdump-rtl-combine-details" } */ -/* { dg-final { scan-rtl-dump "narrow comparison from mode DI to SI" "combine" } } */ +/* { dg-final { scan-rtl-dump "narrow comparison from mode .I to SI" "combine" } } */ typedef __UINT64_TYPE__ uint64_t;