[llvm] r365061 - [X86] Avoid SFB - Skip meta instructions
Robert Lougher via llvm-commits
llvm-commits at lists.llvm.org
Wed Jul 3 10:43:56 PDT 2019
Author: rlougher
Date: Wed Jul 3 10:43:55 2019
New Revision: 365061
URL: http://llvm.org/viewvc/llvm-project?rev=365061&view=rev
Log:
[X86] Avoid SFB - Skip meta instructions
This patch generalizes the fix in D61680 to ignore all meta instructions,
not just debug info.
Patch by Chris Dawson.
Differential Revision: https://reviews.llvm.org/D62605
Added:
llvm/trunk/test/CodeGen/X86/avoid-sfb-ignore-meta.mir
Modified:
llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h
llvm/trunk/lib/Target/X86/X86AvoidStoreForwardingBlocks.cpp
Modified: llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h?rev=365061&r1=365060&r2=365061&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h (original)
+++ llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h Wed Jul 3 10:43:55 2019
@@ -947,6 +947,28 @@ inline IterT skipDebugInstructionsBackwa
return It;
}
+/// Increment \p It until it points to a non-meta instruction or to \p End
+/// and return the resulting iterator. This function should only be used
+/// MachineBasicBlock::{iterator, const_iterator, instr_iterator,
+/// const_instr_iterator} and the respective reverse iterators.
+template <typename IterT>
+inline IterT skipMetaInstructionsForward(IterT It, IterT End) {
+ while (It != End && It->isMetaInstruction())
+ It++;
+ return It;
+}
+
+/// Decrement \p It until it points to a non-meta instruction or to \p Begin
+/// and return the resulting iterator. This function should only be used
+/// MachineBasicBlock::{iterator, const_iterator, instr_iterator,
+/// const_instr_iterator} and the respective reverse iterators.
+template <class IterT>
+inline IterT skipMetaInstructionsBackward(IterT It, IterT Begin) {
+ while (It != Begin && It->isMetaInstruction())
+ It--;
+ return It;
+}
+
} // end namespace llvm
#endif // LLVM_CODEGEN_MACHINEBASICBLOCK_H
Modified: llvm/trunk/lib/Target/X86/X86AvoidStoreForwardingBlocks.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86AvoidStoreForwardingBlocks.cpp?rev=365061&r1=365060&r2=365061&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86AvoidStoreForwardingBlocks.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86AvoidStoreForwardingBlocks.cpp Wed Jul 3 10:43:55 2019
@@ -408,7 +408,7 @@ void X86AvoidSFBPass::buildCopy(MachineI
// If the load and store are consecutive, use the loadInst location to
// reduce register pressure.
MachineInstr *StInst = StoreInst;
- auto PrevInstrIt = skipDebugInstructionsBackward(
+ auto PrevInstrIt = skipMetaInstructionsBackward(
std::prev(MachineBasicBlock::instr_iterator(StoreInst)),
MBB->instr_begin());
if (PrevInstrIt.getNodePtr() == LoadInst)
@@ -496,7 +496,7 @@ void X86AvoidSFBPass::buildCopies(int Si
static void updateKillStatus(MachineInstr *LoadInst, MachineInstr *StoreInst) {
MachineOperand &LoadBase = getBaseOperand(LoadInst);
MachineOperand &StoreBase = getBaseOperand(StoreInst);
- auto StorePrevNonDbgInstr = skipDebugInstructionsBackward(
+ auto StorePrevNonMetaInstr = skipMetaInstructionsBackward(
std::prev(MachineBasicBlock::instr_iterator(StoreInst)),
LoadInst->getParent()->instr_begin()).getNodePtr();
if (LoadBase.isReg()) {
@@ -505,13 +505,13 @@ static void updateKillStatus(MachineInst
// then the partial copies were also created in
// a consecutive order to reduce register pressure,
// and the location of the last load is before the last store.
- if (StorePrevNonDbgInstr == LoadInst)
+ if (StorePrevNonMetaInstr == LoadInst)
LastLoad = LoadInst->getPrevNode()->getPrevNode();
getBaseOperand(LastLoad).setIsKill(LoadBase.isKill());
}
if (StoreBase.isReg()) {
MachineInstr *StInst = StoreInst;
- if (StorePrevNonDbgInstr == LoadInst)
+ if (StorePrevNonMetaInstr == LoadInst)
StInst = LoadInst;
getBaseOperand(StInst->getPrevNode()).setIsKill(StoreBase.isKill());
}
Added: llvm/trunk/test/CodeGen/X86/avoid-sfb-ignore-meta.mir
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/avoid-sfb-ignore-meta.mir?rev=365061&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/avoid-sfb-ignore-meta.mir (added)
+++ llvm/trunk/test/CodeGen/X86/avoid-sfb-ignore-meta.mir Wed Jul 3 10:43:55 2019
@@ -0,0 +1,155 @@
+# RUN: llc %s -run-pass x86-avoid-SFB -mtriple=x86_64-unknown-linux-gnu -o - | FileCheck %s
+#
+# This was generated from:
+#
+# using alpha = float __attribute__((ext_vector_type(4)));
+#
+# void bravo(alpha * __restrict__ p1, alpha * __restrict__ p2) {
+# char *p3 = (char *)p1;
+# *p3 = 0;
+# alpha t = *p1;
+# *p2 = t;
+# }
+#
+# Using the command line:
+# clang -g -c 1.cpp -O2 -S -emit-llvm -fno-strict-aliasing --target=x86_64-unknown-unknown -o test.ll
+# llc -stop-before=x86-avoid-SFB test.ll -o before.mir
+#
+# The debug instruction between the load and the store has been manually replaced with a CFI meta instruction.
+
+--- |
+ ; ModuleID = 'test.ll'
+ source_filename = "1.cpp"
+ target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+ target triple = "x86_64-unknown-unknown"
+
+ ; Function Attrs: norecurse nounwind uwtable
+ define dso_local void @debug(<4 x float>* noalias nocapture %p1, <4 x float>* noalias nocapture %p2) local_unnamed_addr !dbg !10 {
+ entry:
+ call void @llvm.dbg.value(metadata <4 x float>* %p1, metadata !21, metadata !DIExpression()), !dbg !25
+ call void @llvm.dbg.value(metadata <4 x float>* %p2, metadata !22, metadata !DIExpression()), !dbg !25
+ %0 = bitcast <4 x float>* %p1 to i8*, !dbg !26
+ call void @llvm.dbg.value(metadata i8* %0, metadata !23, metadata !DIExpression()), !dbg !25
+ store i8 0, i8* %0, align 1, !dbg !27
+ %1 = load <4 x float>, <4 x float>* %p1, align 16, !dbg !28
+ call void @llvm.dbg.value(metadata <4 x float> %1, metadata !24, metadata !DIExpression()), !dbg !25
+ store <4 x float> %1, <4 x float>* %p2, align 16, !dbg !29
+ ret void, !dbg !30
+ }
+
+ ; Function Attrs: nounwind readnone speculatable
+ declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+ ; Function Attrs: nounwind
+ declare void @llvm.stackprotector(i8*, i8**)
+
+ !llvm.dbg.cu = !{!0}
+ !llvm.module.flags = !{!6, !7, !8}
+ !llvm.ident = !{!9}
+
+ !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 9.0.0 (https://github.com/llvm/llvm-project.git 9afc4764dd24bd2f23c44e51ad33f8e58234a8b6)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None)
+ !1 = !DIFile(filename: "1.cpp", directory: "C:\5CUsers\5Cgbdawsoc\5CDocuments\5Cllvm\5Cbg40969")
+ !2 = !{}
+ !3 = !{!4}
+ !4 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !5, size: 64)
+ !5 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
+ !6 = !{i32 2, !"Dwarf Version", i32 4}
+ !7 = !{i32 2, !"Debug Info Version", i32 3}
+ !8 = !{i32 1, !"wchar_size", i32 4}
+ !9 = !{!"clang version 9.0.0 (https://github.com/llvm/llvm-project.git 9afc4764dd24bd2f23c44e51ad33f8e58234a8b6)"}
+ !10 = distinct !DISubprogram(name: "bravo", linkageName: "_Z5bravoPDv4_fS0_", scope: !1, file: !1, line: 4, type: !11, scopeLine: 4, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !20)
+ !11 = !DISubroutineType(types: !12)
+ !12 = !{null, !13, !13}
+ !13 = !DIDerivedType(tag: DW_TAG_restrict_type, baseType: !14)
+ !14 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !15, size: 64)
+ !15 = !DIDerivedType(tag: DW_TAG_typedef, name: "alpha", file: !1, line: 2, baseType: !16)
+ !16 = !DICompositeType(tag: DW_TAG_array_type, baseType: !17, size: 128, flags: DIFlagVector, elements: !18)
+ !17 = !DIBasicType(name: "float", size: 32, encoding: DW_ATE_float)
+ !18 = !{!19}
+ !19 = !DISubrange(count: 4)
+ !20 = !{!21, !22, !23, !24}
+ !21 = !DILocalVariable(name: "p1", arg: 1, scope: !10, file: !1, line: 4, type: !13)
+ !22 = !DILocalVariable(name: "p2", arg: 2, scope: !10, file: !1, line: 4, type: !13)
+ !23 = !DILocalVariable(name: "p3", scope: !10, file: !1, line: 5, type: !4)
+ !24 = !DILocalVariable(name: "t", scope: !10, file: !1, line: 7, type: !15)
+ !25 = !DILocation(line: 0, scope: !10)
+ !26 = !DILocation(line: 5, column: 14, scope: !10)
+ !27 = !DILocation(line: 6, column: 7, scope: !10)
+ !28 = !DILocation(line: 7, column: 13, scope: !10)
+ !29 = !DILocation(line: 8, column: 7, scope: !10)
+ !30 = !DILocation(line: 9, column: 1, scope: !10)
+
+...
+---
+name: debug
+alignment: 4
+exposesReturnsTwice: false
+legalized: false
+regBankSelected: false
+selected: false
+failedISel: false
+tracksRegLiveness: true
+hasWinCFI: false
+registers:
+ - { id: 0, class: gr64, preferred-register: '' }
+ - { id: 1, class: gr64, preferred-register: '' }
+ - { id: 2, class: vr128, preferred-register: '' }
+liveins:
+ - { reg: '$rdi', virtual-reg: '%0' }
+ - { reg: '$rsi', virtual-reg: '%1' }
+frameInfo:
+ isFrameAddressTaken: false
+ isReturnAddressTaken: false
+ hasStackMap: false
+ hasPatchPoint: false
+ stackSize: 0
+ offsetAdjustment: 0
+ maxAlignment: 0
+ adjustsStack: false
+ hasCalls: false
+ stackProtector: ''
+ maxCallFrameSize: 4294967295
+ cvBytesOfCalleeSavedRegisters: 0
+ hasOpaqueSPAdjustment: false
+ hasVAStart: false
+ hasMustTailInVarArgFunc: false
+ localFrameSize: 0
+ savePoint: ''
+ restorePoint: ''
+fixedStack: []
+stack: []
+constants: []
+machineFunctionInfo: {}
+body: |
+ bb.0.entry:
+ liveins: $rdi, $rsi
+
+ DBG_VALUE $rdi, $noreg, !21, !DIExpression(), debug-location !25
+ DBG_VALUE $rsi, $noreg, !22, !DIExpression(), debug-location !25
+ %1:gr64 = COPY $rsi
+ DBG_VALUE %1, $noreg, !22, !DIExpression(), debug-location !25
+ %0:gr64 = COPY $rdi
+ DBG_VALUE %0, $noreg, !21, !DIExpression(), debug-location !25
+ DBG_VALUE %0, $noreg, !23, !DIExpression(), debug-location !25
+ MOV8mi %0, 1, $noreg, 0, $noreg, 0, debug-location !27 :: (store 1 into %ir.0)
+ %2:vr128 = MOVAPSrm %0, 1, $noreg, 0, $noreg, debug-location !28 :: (load 16 from %ir.p1)
+ CFI_INSTRUCTION offset $r13, -123
+ MOVAPSmr %1, 1, $noreg, 0, $noreg, killed %2, debug-location !29 :: (store 16 into %ir.p2)
+ RET 0, debug-location !30
+
+ ; CHECK-LABEL: name: debug
+ ; CHECK: %1:gr64 = COPY
+ ; CHECK: %0:gr64 = COPY
+ ; CHECK: MOV8mi
+ ; CHECK: %3:gr8 = MOV8rm
+ ; CHECK: MOV8mr
+ ; CHECK: %4:gr64 = MOV64rm
+ ; CHECK: MOV64mr
+ ; CHECK: %5:gr32 = MOV32rm
+ ; CHECK: MOV32mr
+ ; CHECK: %6:gr16 = MOV16rm
+ ; CHECK: MOV16mr
+ ; CHECK: %7:gr8 = MOV8rm
+ ; CHECK: MOV8mr
+ ; CHECK: RET 0
+...
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