From patchwork Wed Dec 12 16:37:22 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Hubicka X-Patchwork-Id: 205576 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) by ozlabs.org (Postfix) with SMTP id 62F6D2C0087 for ; Thu, 13 Dec 2012 03:37:49 +1100 (EST) Comment: DKIM? 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The preference to > the MOVs are good for old CPU micro-architectures (before pentium-4, > K10), because it breaks the data dependency. In modern > micro-architecture, push/pop is implemented using a mechanism called > stack engine. The data dependency is removed by the hardware, and > push/pop becomes very cheap (1 uOp, 1 cycle latency), and they are > smaller. There is no longer the need to avoid using them. This is > also what ICC does. > > The following patch fixed the problem. It passes bootstrap/regression > test. OK to install? > > thanks, > > David > > Index: config/i386/i386.c > =================================================================== > --- config/i386/i386.c (revision 194324) > +++ config/i386/i386.c (working copy) > @@ -1919,10 +1919,10 @@ static unsigned int initial_ix86_tune_fe > m_P4_NOCONA | m_CORE2I7 | m_ATOM | m_AMD_MULTIPLE | m_GENERIC, > > /* X86_TUNE_PROLOGUE_USING_MOVE */ > - m_PPRO | m_CORE2I7 | m_ATOM | m_ATHLON_K8 | m_GENERIC, > + m_PPRO | m_ATHLON_K8, > > /* X86_TUNE_EPILOGUE_USING_MOVE */ > - m_PPRO | m_CORE2I7 | m_ATOM | m_ATHLON_K8 | m_GENERIC, > + m_PPRO | m_ATHLON_K8, Push/pops wrt moves was always difficult to tune on old CPUs, so I am happy it is gone from generic (in fact I had similar patch pending). Are you sure about Atom having stack engine, too? Related thing is accumulate_outgoing_args. Igor is testing it on Core and I will give it a try on K10. Honza I am attaching the changes for core costs I made if someone is interested in testing them. If we can declare P4/PPRo and maybe K8 chips obsolette for generic, there is room for improvement in generic, too. Like using inc/dec again. Honza Index: config/i386/i386.c =================================================================== --- config/i386/i386.c (revision 194452) +++ config/i386/i386.c (working copy) @@ -1620,14 +1620,14 @@ struct processor_costs core_cost = { COSTS_N_INSNS (8), /* cost of FABS instruction. */ COSTS_N_INSNS (8), /* cost of FCHS instruction. */ COSTS_N_INSNS (40), /* cost of FSQRT instruction. */ - {{libcall, {{1024, rep_prefix_4_byte, true}, {-1, libcall, false}}}, - {libcall, {{24, loop, true}, {128, rep_prefix_8_byte, true}, + {{libcall, {{8192, rep_prefix_4_byte, true}, {-1, libcall, false}}}, + {libcall, {{24, loop, true}, {8192, rep_prefix_8_byte, true}, {-1, libcall, false}}}}, {{libcall, {{6, loop_1_byte, true}, {24, loop, true}, {8192, rep_prefix_4_byte, true}, {-1, libcall, false}}}, - {libcall, {{24, loop, true}, {512, rep_prefix_8_byte, true}, + {libcall, {{24, loop, true}, {8192, rep_prefix_8_byte, true}, {-1, libcall, false}}}}, 1, /* scalar_stmt_cost. */ 1, /* scalar load_cost. */ @@ -1806,7 +1806,7 @@ static unsigned int initial_ix86_tune_fe m_PPRO, /* X86_TUNE_PARTIAL_FLAG_REG_STALL */ - m_CORE2I7 | m_GENERIC, + m_GENERIC | m_CORE2, /* X86_TUNE_LCP_STALL: Avoid an expensive length-changing prefix stall * on 16-bit immediate moves into memory on Core2 and Corei7. */ @@ -1822,7 +1822,7 @@ static unsigned int initial_ix86_tune_fe m_K6, /* X86_TUNE_USE_CLTD */ - ~(m_PENT | m_ATOM | m_K6), + ~(m_PENT | m_ATOM | m_K6 | m_GENERIC), /* X86_TUNE_USE_XCHGB: Use xchgb %rh,%rl instead of rolw/rorw $8,rx. */ m_PENT4, @@ -1901,7 +1901,7 @@ static unsigned int initial_ix86_tune_fe m_COREI7 | m_BDVER, /* X86_TUNE_SSE_PACKED_SINGLE_INSN_OPTIMAL */ - m_BDVER , + m_BDVER, /* X86_TUNE_SSE_SPLIT_REGS: Set for machines where the type and dependencies are resolved on SSE register parts instead of whole registers, so we may @@ -1910,10 +1910,10 @@ static unsigned int initial_ix86_tune_fe m_ATHLON_K8, /* X86_TUNE_SSE_TYPELESS_STORES */ - m_AMD_MULTIPLE, + m_AMD_MULTIPLE | m_CORE2I7, /*????*/ /* X86_TUNE_SSE_LOAD0_BY_PXOR */ - m_PPRO | m_P4_NOCONA, + m_PPRO | m_P4_NOCONA | m_CORE2I7, /*????*/ /* X86_TUNE_MEMORY_MISMATCH_STALL */ m_P4_NOCONA | m_CORE2I7 | m_ATOM | m_AMD_MULTIPLE | m_GENERIC, @@ -1938,7 +1938,7 @@ static unsigned int initial_ix86_tune_fe /* X86_TUNE_FOUR_JUMP_LIMIT: Some CPU cores are not able to predict more than 4 branch instructions in the 16 byte window. */ - m_PPRO | m_P4_NOCONA | m_CORE2I7 | m_ATOM | m_AMD_MULTIPLE | m_GENERIC, + m_PPRO | m_P4_NOCONA | m_ATOM | m_AMD_MULTIPLE | m_GENERIC, /* X86_TUNE_SCHEDULE */ m_PENT | m_PPRO | m_CORE2I7 | m_ATOM | m_K6_GEODE | m_AMD_MULTIPLE | m_GENERIC, @@ -1947,10 +1947,10 @@ static unsigned int initial_ix86_tune_fe m_CORE2I7 | m_ATOM | m_AMD_MULTIPLE | m_GENERIC, /* X86_TUNE_USE_INCDEC */ - ~(m_P4_NOCONA | m_CORE2I7 | m_ATOM | m_GENERIC), + ~(m_P4_NOCONA | m_ATOM | m_GENERIC), /* X86_TUNE_PAD_RETURNS */ - m_CORE2I7 | m_AMD_MULTIPLE | m_GENERIC, + m_AMD_MULTIPLE | m_GENERIC, /* X86_TUNE_PAD_SHORT_FUNCTION: Pad short funtion. */ m_ATOM, @@ -1959,7 +1959,7 @@ static unsigned int initial_ix86_tune_fe m_PPRO | m_P4_NOCONA | m_CORE2I7 | m_ATOM | m_K6_GEODE | m_ATHLON_K8 | m_GENERIC, /* X86_TUNE_AVOID_VECTOR_DECODE */ - m_CORE2I7 | m_K8 | m_GENERIC64, + m_K8 | m_GENERIC64, /* X86_TUNE_PROMOTE_HIMODE_IMUL: Modern CPUs have same latency for HImode and SImode multiply, but 386 and 486 do HImode multiply faster. */ @@ -1967,11 +1967,11 @@ static unsigned int initial_ix86_tune_fe /* X86_TUNE_SLOW_IMUL_IMM32_MEM: Imul of 32-bit constant and memory is vector path on AMD machines. */ - m_CORE2I7 | m_K8 | m_AMDFAM10 | m_BDVER | m_BTVER | m_GENERIC64, + m_CORE2I7 | m_K8 | m_AMDFAM10 | m_BDVER | m_BTVER, /* X86_TUNE_SLOW_IMUL_IMM8: Imul of 8-bit constant is vector path on AMD machines. */ - m_CORE2I7 | m_K8 | m_AMDFAM10 | m_BDVER | m_BTVER | m_GENERIC64, + m_CORE2I7 | m_K8 | m_AMDFAM10 | m_BDVER | m_BTVER, /* X86_TUNE_MOVE_M1_VIA_OR: On pentiums, it is faster to load -1 via OR than a MOV. */ @@ -1988,7 +1988,7 @@ static unsigned int initial_ix86_tune_fe /* X86_TUNE_USE_VECTOR_FP_CONVERTS: Prefer vector packed SSE conversion from FP to FP. */ - m_CORE2I7 | m_AMDFAM10 | m_GENERIC, + m_AMDFAM10 | m_GENERIC, /* X86_TUNE_USE_VECTOR_CONVERTS: Prefer vector packed SSE conversion from integer to FP. */ @@ -1997,7 +1997,7 @@ static unsigned int initial_ix86_tune_fe /* X86_TUNE_FUSE_CMP_AND_BRANCH: Fuse a compare or test instruction with a subsequent conditional jump instruction into a single compare-and-branch uop. */ - m_BDVER, + m_BDVER | m_CORE2I7, /* X86_TUNE_OPT_AGU: Optimize for Address Generation Unit. This flag will impact LEA instruction selection. */ @@ -2052,7 +2052,7 @@ static unsigned int initial_ix86_arch_fe }; static const unsigned int x86_accumulate_outgoing_args - = m_PPRO | m_P4_NOCONA | m_ATOM | m_CORE2I7 | m_AMD_MULTIPLE | m_GENERIC; + = m_PPRO | m_P4_NOCONA | m_ATOM | m_AMD_MULTIPLE | m_GENERIC; static const unsigned int x86_arch_always_fancy_math_387 = m_PENT | m_PPRO | m_P4_NOCONA | m_CORE2I7 | m_ATOM | m_AMD_MULTIPLE | m_GENERIC; Index: config/i386/i386.md =================================================================== --- config/i386/i386.md (revision 194452) +++ config/i386/i386.md (working copy) @@ -965,7 +965,7 @@ (compare:CC (match_operand:SDWIM 1 "nonimmediate_operand") (match_operand:SDWIM 2 ""))) (set (pc) (if_then_else - (match_operator 0 "ordered_comparison_operator" + (match_operator 0 "comparison_operator" [(reg:CC FLAGS_REG) (const_int 0)]) (label_ref (match_operand 3)) (pc)))] @@ -983,7 +983,7 @@ (compare:CC (match_operand:SWIM 2 "nonimmediate_operand") (match_operand:SWIM 3 ""))) (set (match_operand:QI 0 "register_operand") - (match_operator 1 "ordered_comparison_operator" + (match_operator 1 "comparison_operator" [(reg:CC FLAGS_REG) (const_int 0)]))] "" {