From ca90b1ed9ac7e9aaacb3ef0eb055d2f594d30493 Mon Sep 17 00:00:00 2001 From: Yuri Rumyantsev Date: Mon, 11 Jan 2016 12:07:31 +0000 Subject: re PR rtl-optimization/68920 (Undesirable if-conversion for a rarely taken branch) gcc/ 2016-01-11 Yuri Rumyantsev PR rtl-optimization/68920 * config/i386/i386.c (ix86_option_override_internal): Restrict number of conditional moves for RTL if-conversion to 1 for TARGET_ONE_IF_CONV_INSN. * config/i386/i386.h (TARGET_ONE_IF_CONV_INSN): New macros. * config/i386/x86-tune.def (X86_TUNE_ONE_IF_CONV_INSN): New macros. * params.def (PARAM_MAX_RTL_IF_CONVERSION_INSNS) : Introduce new parameter to restirct number of conditional moves for RTL if-conversion. * doc/invoke.texi (max-rtl-if-conversion-insns): Document it. * ifcvt.c (bb_ok_for_noce_convert_multiple_sets): Limit number of conditionl moves. gcc/testsuite/ 2016-01-11 Yuri Rumyantsev PR rtl-optimization/68920 * gcc.dg/ifcvt-4.c: Add "--param max-rtl-if-conversion-insns=3" option for ix86 targets. * gcc.dg/ifcvt-5.c: New test. From-SVN: r232220 --- gcc/config/i386/i386.c | 7 +++++++ gcc/config/i386/i386.h | 2 ++ gcc/config/i386/x86-tune.def | 5 +++++ 3 files changed, 14 insertions(+) (limited to 'gcc/config') diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index aac0847db7e..c0b2cce4f3f 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -5343,6 +5343,13 @@ ix86_option_override_internal (bool main_args_p, opts->x_param_values, opts_set->x_param_values); + /* Restrict number of if-converted SET insns to 1. */ + if (TARGET_ONE_IF_CONV_INSN) + maybe_set_param_value (PARAM_MAX_RTL_IF_CONVERSION_INSNS, + 1, + opts->x_param_values, + opts_set->x_param_values); + /* Enable sw prefetching at -O3 for CPUS that prefetching is helpful. */ if (opts->x_flag_prefetch_loop_arrays < 0 && HAVE_prefetch diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h index befed85721c..dcaa011a2be 100644 --- a/gcc/config/i386/i386.h +++ b/gcc/config/i386/i386.h @@ -499,6 +499,8 @@ extern unsigned char ix86_tune_features[X86_TUNE_LAST]; ix86_tune_features[X86_TUNE_ADJUST_UNROLL] #define TARGET_AVOID_FALSE_DEP_FOR_BMI \ ix86_tune_features[X86_TUNE_AVOID_FALSE_DEP_FOR_BMI] +#define TARGET_ONE_IF_CONV_INSN \ + ix86_tune_features[X86_TUNE_ONE_IF_CONV_INSN] /* Feature tests against the various architecture variations. */ enum ix86_arch_indices { diff --git a/gcc/config/i386/x86-tune.def b/gcc/config/i386/x86-tune.def index 88ed50aa860..9d25e51d407 100644 --- a/gcc/config/i386/x86-tune.def +++ b/gcc/config/i386/x86-tune.def @@ -550,3 +550,8 @@ DEF_TUNE (X86_TUNE_PROMOTE_QI_REGS, "promote_qi_regs", 0) unrolling small loop less important. For, such architectures we adjust the unroll factor so that the unrolled loop fits the loop buffer. */ DEF_TUNE (X86_TUNE_ADJUST_UNROLL, "adjust_unroll_factor", m_BDVER3 | m_BDVER4) + +/* X86_TUNE_ONE_IF_CONV_INSNS: Restrict a number of set insns to be + if-converted to one. */ +DEF_TUNE (X86_TUNE_ONE_IF_CONV_INSN, "one_if_conv_insn", + m_SILVERMONT | m_KNL | m_INTEL | m_CORE_ALL | m_GENERIC) -- cgit v1.2.1