From: Pat Haugen Date: Tue, 19 Sep 2023 18:19:59 +0000 (-0500) Subject: Disable generation of scalar modulo instructions. X-Git-Tag: basepoints/gcc-15~5989 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=58ab38213b979811d314f68e3f455c28a1d44140;p=thirdparty%2Fgcc.git Disable generation of scalar modulo instructions. It was recently discovered that the scalar modulo instructions can suffer noticeable performance issues for certain input values. This patch disables their generation since the equivalent div/mul/sub sequence does not suffer the same problem. gcc/ * config/rs6000/rs6000.cc (rs6000_rtx_costs): Check whether the modulo instruction is disabled. * config/rs6000/rs6000.h (RS6000_DISABLE_SCALAR_MODULO): New. * config/rs6000/rs6000.md (mod3, *mod3): Check it. (define_expand umod3): New. (define_insn umod3): Rename to *umod3 and check if the modulo instruction is disabled. (umodti3, modti3): Check if the modulo instruction is disabled. gcc/testsuite/ * gcc.target/powerpc/clone1.c: Add xfails. * gcc.target/powerpc/clone3.c: Likewise. * gcc.target/powerpc/mod-1.c: Update scan strings and add xfails. * gcc.target/powerpc/mod-2.c: Likewise. * gcc.target/powerpc/p10-vdivq-vmodq.c: Add xfails. --- diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc index efe9adce1f8b..caf9eeee5ef1 100644 --- a/gcc/config/rs6000/rs6000.cc +++ b/gcc/config/rs6000/rs6000.cc @@ -22164,7 +22164,9 @@ rs6000_rtx_costs (rtx x, machine_mode mode, int outer_code, *total = rs6000_cost->divsi; } /* Add in shift and subtract for MOD unless we have a mod instruction. */ - if (!TARGET_MODULO && (code == MOD || code == UMOD)) + if ((!TARGET_MODULO + || (RS6000_DISABLE_SCALAR_MODULO && SCALAR_INT_MODE_P (mode))) + && (code == MOD || code == UMOD)) *total += COSTS_N_INSNS (2); return false; diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h index 3503614efbd6..22595f6ebd77 100644 --- a/gcc/config/rs6000/rs6000.h +++ b/gcc/config/rs6000/rs6000.h @@ -2492,3 +2492,9 @@ while (0) rs6000_asm_output_opcode (STREAM); \ } \ while (0) + +/* Disable generation of scalar modulo instructions due to performance issues + with certain input values. This can be removed in the future when the + issues have been resolved. */ +#define RS6000_DISABLE_SCALAR_MODULO 1 + diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md index 1a9a7b1a4791..7b583d7a69ad 100644 --- a/gcc/config/rs6000/rs6000.md +++ b/gcc/config/rs6000/rs6000.md @@ -3424,6 +3424,17 @@ FAIL; operands[2] = force_reg (mode, operands[2]); + + if (RS6000_DISABLE_SCALAR_MODULO) + { + temp1 = gen_reg_rtx (mode); + temp2 = gen_reg_rtx (mode); + + emit_insn (gen_div3 (temp1, operands[1], operands[2])); + emit_insn (gen_mul3 (temp2, temp1, operands[2])); + emit_insn (gen_sub3 (operands[0], operands[1], temp2)); + DONE; + } } else { @@ -3443,17 +3454,36 @@ [(set (match_operand:GPR 0 "gpc_reg_operand" "=&r,r") (mod:GPR (match_operand:GPR 1 "gpc_reg_operand" "r,r") (match_operand:GPR 2 "gpc_reg_operand" "r,r")))] - "TARGET_MODULO" + "TARGET_MODULO && !RS6000_DISABLE_SCALAR_MODULO" "mods %0,%1,%2" [(set_attr "type" "div") (set_attr "size" "")]) +;; This define_expand can be removed when RS6000_DISABLE_SCALAR_MODULO is +;; removed. +(define_expand "umod3" + [(set (match_operand:GPR 0 "gpc_reg_operand") + (umod:GPR (match_operand:GPR 1 "gpc_reg_operand") + (match_operand:GPR 2 "gpc_reg_operand")))] + "TARGET_MODULO" +{ + if (RS6000_DISABLE_SCALAR_MODULO) + { + rtx temp1 = gen_reg_rtx (mode); + rtx temp2 = gen_reg_rtx (mode); + + emit_insn (gen_udiv3 (temp1, operands[1], operands[2])); + emit_insn (gen_mul3 (temp2, temp1, operands[2])); + emit_insn (gen_sub3 (operands[0], operands[1], temp2)); + DONE; + } +}) -(define_insn "umod3" +(define_insn "*umod3" [(set (match_operand:GPR 0 "gpc_reg_operand" "=&r,r") (umod:GPR (match_operand:GPR 1 "gpc_reg_operand" "r,r") (match_operand:GPR 2 "gpc_reg_operand" "r,r")))] - "TARGET_MODULO" + "TARGET_MODULO && !RS6000_DISABLE_SCALAR_MODULO" "modu %0,%1,%2" [(set_attr "type" "div") (set_attr "size" "")]) @@ -3510,7 +3540,7 @@ [(set (match_operand:TI 0 "altivec_register_operand" "=v") (umod:TI (match_operand:TI 1 "altivec_register_operand" "v") (match_operand:TI 2 "altivec_register_operand" "v")))] - "TARGET_POWER10 && TARGET_POWERPC64" + "TARGET_POWER10 && TARGET_POWERPC64 && !RS6000_DISABLE_SCALAR_MODULO" "vmoduq %0,%1,%2" [(set_attr "type" "vecdiv") (set_attr "size" "128")]) @@ -3519,7 +3549,7 @@ [(set (match_operand:TI 0 "altivec_register_operand" "=v") (mod:TI (match_operand:TI 1 "altivec_register_operand" "v") (match_operand:TI 2 "altivec_register_operand" "v")))] - "TARGET_POWER10 && TARGET_POWERPC64" + "TARGET_POWER10 && TARGET_POWERPC64 && !RS6000_DISABLE_SCALAR_MODULO" "vmodsq %0,%1,%2" [(set_attr "type" "vecdiv") (set_attr "size" "128")]) diff --git a/gcc/testsuite/gcc.target/powerpc/clone1.c b/gcc/testsuite/gcc.target/powerpc/clone1.c index c69fd2aa1b87..74323ca0e8c1 100644 --- a/gcc/testsuite/gcc.target/powerpc/clone1.c +++ b/gcc/testsuite/gcc.target/powerpc/clone1.c @@ -21,6 +21,7 @@ long mod_func_or (long a, long b, long c) return mod_func (a, b) | c; } -/* { dg-final { scan-assembler-times {\mdivd\M} 1 } } */ -/* { dg-final { scan-assembler-times {\mmulld\M} 1 } } */ -/* { dg-final { scan-assembler-times {\mmodsd\M} 1 } } */ +/* { Fail due to RS6000_DISABLE_SCALAR_MODULO. */ +/* { dg-final { scan-assembler-times {\mdivd\M} 1 { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-times {\mmulld\M} 1 { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-times {\mmodsd\M} 1 { xfail *-*-* } } } */ diff --git a/gcc/testsuite/gcc.target/powerpc/clone3.c b/gcc/testsuite/gcc.target/powerpc/clone3.c index 911b88b781d1..d3eb4dd2378c 100644 --- a/gcc/testsuite/gcc.target/powerpc/clone3.c +++ b/gcc/testsuite/gcc.target/powerpc/clone3.c @@ -27,7 +27,8 @@ long mod_func_or (long a, long b, long c) return mod_func (a, b) | c; } -/* { dg-final { scan-assembler-times {\mdivd\M} 1 } } */ -/* { dg-final { scan-assembler-times {\mmulld\M} 1 } } */ -/* { dg-final { scan-assembler-times {\mmodsd\M} 2 } } */ +/* { Fail due to RS6000_DISABLE_SCALAR_MODULO. */ +/* { dg-final { scan-assembler-times {\mdivd\M} 1 { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-times {\mmulld\M} 1 { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-times {\mmodsd\M} 2 { xfail *-*-* } } } */ /* { dg-final { scan-assembler-times {\mpld\M} 1 } } */ diff --git a/gcc/testsuite/gcc.target/powerpc/mod-1.c b/gcc/testsuite/gcc.target/powerpc/mod-1.c index 861ba670af4d..8720ffb33460 100644 --- a/gcc/testsuite/gcc.target/powerpc/mod-1.c +++ b/gcc/testsuite/gcc.target/powerpc/mod-1.c @@ -7,13 +7,14 @@ long lsmod (long a, long b) { return a%b; } unsigned int iumod (unsigned int a, unsigned int b) { return a%b; } unsigned long lumod (unsigned long a, unsigned long b) { return a%b; } -/* { dg-final { scan-assembler-times "modsw " 1 } } */ -/* { dg-final { scan-assembler-times "modsd " 1 } } */ -/* { dg-final { scan-assembler-times "moduw " 1 } } */ -/* { dg-final { scan-assembler-times "modud " 1 } } */ -/* { dg-final { scan-assembler-not "mullw " } } */ -/* { dg-final { scan-assembler-not "mulld " } } */ -/* { dg-final { scan-assembler-not "divw " } } */ -/* { dg-final { scan-assembler-not "divd " } } */ -/* { dg-final { scan-assembler-not "divwu " } } */ -/* { dg-final { scan-assembler-not "divdu " } } */ +/* { Fail due to RS6000_DISABLE_SCALAR_MODULO. */ +/* { dg-final { scan-assembler-times {\mmodsw\M} 1 { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-times {\mmodsd\M} 1 { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-times {\mmoduw\M} 1 { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-times {\mmodud\M} 1 { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-not {\mmullw\M} { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-not {\mmulld\M} { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-not {\mdivw\M} { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-not {\mdivd\M} { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-not {\mdivwu\M} { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-not {\mdivdu\M} { xfail *-*-* } } } */ diff --git a/gcc/testsuite/gcc.target/powerpc/mod-2.c b/gcc/testsuite/gcc.target/powerpc/mod-2.c index 441ec5878f1c..54bdca886078 100644 --- a/gcc/testsuite/gcc.target/powerpc/mod-2.c +++ b/gcc/testsuite/gcc.target/powerpc/mod-2.c @@ -5,8 +5,9 @@ int ismod (int a, int b) { return a%b; } unsigned int iumod (unsigned int a, unsigned int b) { return a%b; } -/* { dg-final { scan-assembler-times "modsw " 1 } } */ -/* { dg-final { scan-assembler-times "moduw " 1 } } */ -/* { dg-final { scan-assembler-not "mullw " } } */ -/* { dg-final { scan-assembler-not "divw " } } */ -/* { dg-final { scan-assembler-not "divwu " } } */ +/* { Fail due to RS6000_DISABLE_SCALAR_MODULO. */ +/* { dg-final { scan-assembler-times {\mmodsw\M} 1 { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-times {\mmoduw\M} 1 { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-not {\mmullw\M} { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-not {\mdivw\M} { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-not {\mdivwu\M} { xfail *-*-* } } } */ diff --git a/gcc/testsuite/gcc.target/powerpc/p10-vdivq-vmodq.c b/gcc/testsuite/gcc.target/powerpc/p10-vdivq-vmodq.c index 84685e5ff430..148998c8c9d6 100644 --- a/gcc/testsuite/gcc.target/powerpc/p10-vdivq-vmodq.c +++ b/gcc/testsuite/gcc.target/powerpc/p10-vdivq-vmodq.c @@ -23,5 +23,6 @@ __int128 s_mod(__int128 a, __int128 b) /* { dg-final { scan-assembler {\mvdivsq\M} } } */ /* { dg-final { scan-assembler {\mvdivuq\M} } } */ -/* { dg-final { scan-assembler {\mvmodsq\M} } } */ -/* { dg-final { scan-assembler {\mvmoduq\M} } } */ +/* { Fail due to RS6000_DISABLE_SCALAR_MODULO. */ +/* { dg-final { scan-assembler {\mvmodsq\M} { xfail *-*-* } } } */ +/* { dg-final { scan-assembler {\mvmoduq\M} { xfail *-*-* } } } */