LoopVectorizer - skip 'bitcast' between GEP and load.

Skipping 'bitcast' in this case allows to vectorize load:

  %arrayidx = getelementptr inbounds double*, double** %in, i64 %indvars.iv
  %tmp53 = bitcast double** %arrayidx to i64*
  %tmp54 = load i64, i64* %tmp53, align 8

Differential Revision http://reviews.llvm.org/D14112

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251907 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp
index 40d9488fddcb8fd00424108accec3ad9bdbb57f4..1a6021cb3c88d3804c2ea4c4f04869448e1e564f 100644 (file)
--- a/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -268,6 +268,32 @@ static Type* ToVectorTy(Type *Scalar, unsigned VF) {
   return VectorType::get(Scalar, VF);
 }
 
+/// A helper function that returns GEP instruction and knows to skip a
+/// 'bitcast'. The 'bitcast' may be skipped if the source and the destination
+/// pointee types of the 'bitcast' have the same size.
+/// For example:
+///   bitcast double** %var to i64* - can be skipped
+///   bitcast double** %var to i8*  - can not
+static GetElementPtrInst *getGEPInstruction(Value *Ptr) {
+
+  if (isa<GetElementPtrInst>(Ptr))
+    return cast<GetElementPtrInst>(Ptr);
+
+  if (isa<BitCastInst>(Ptr) &&
+      isa<GetElementPtrInst>(cast<BitCastInst>(Ptr)->getOperand(0))) {
+    Type *BitcastTy = Ptr->getType();
+    Type *GEPTy = cast<BitCastInst>(Ptr)->getSrcTy();
+    if (!isa<PointerType>(BitcastTy) || !isa<PointerType>(GEPTy))
+      return nullptr;
+    Type *Pointee1Ty = cast<PointerType>(BitcastTy)->getPointerElementType();
+    Type *Pointee2Ty = cast<PointerType>(GEPTy)->getPointerElementType();
+    const DataLayout &DL = cast<BitCastInst>(Ptr)->getModule()->getDataLayout();
+    if (DL.getTypeSizeInBits(Pointee1Ty) == DL.getTypeSizeInBits(Pointee2Ty))
+      return cast<GetElementPtrInst>(cast<BitCastInst>(Ptr)->getOperand(0));
+  }
+  return nullptr;
+}
+
 /// InnerLoopVectorizer vectorizes loops which contain only one basic
 /// block to a specified vectorization factor (VF).
 /// This class performs the widening of scalars into vectors, or multiple
@@ -1983,7 +2009,7 @@ int LoopVectorizationLegality::isConsecutivePtr(Value *Ptr) {
     return II.getConsecutiveDirection();
   }
 
-  GetElementPtrInst *Gep = dyn_cast_or_null<GetElementPtrInst>(Ptr);
+  GetElementPtrInst *Gep = getGEPInstruction(Ptr);
   if (!Gep)
     return 0;
 
@@ -2377,7 +2403,7 @@ void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr) {
   VectorParts &Entry = WidenMap.get(Instr);
 
   // Handle consecutive loads/stores.
-  GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr);
+  GetElementPtrInst *Gep = getGEPInstruction(Ptr);
   if (Gep && Legal->isInductionVariable(Gep->getPointerOperand())) {
     setDebugLocFromInst(Builder, Gep);
     Value *PtrOperand = Gep->getPointerOperand();

diff --git a/test/Transforms/LoopVectorize/X86/vectorization-remarks-profitable.ll b/test/Transforms/LoopVectorize/X86/vectorization-remarks-profitable.ll
index dd6bfd0a156ae697982cc5c4a24ddea55a0b526a..82c246e185711616151487d1a50501a2d8f6659f 100644 (file)
--- a/test/Transforms/LoopVectorize/X86/vectorization-remarks-profitable.ll
+++ b/test/Transforms/LoopVectorize/X86/vectorization-remarks-profitable.ll
@@ -1,114 +1,113 @@
 ; RUN: opt < %s -loop-vectorize -pass-remarks-analysis='loop-vectorize' -mtriple=x86_64-unknown-linux -S 2>&1 | FileCheck %s
 
 ; Verify analysis remarks are generated when interleaving is not beneficial.
-; CHECK: remark: vectorization-remarks-profitable.c:4:14: the cost-model indicates that vectorization is not beneficial
-; CHECK: remark: vectorization-remarks-profitable.c:4:14: the cost-model indicates that interleaving is not beneficial and is explicitly disabled or interleave count is set to 1
-; CHECK: remark: vectorization-remarks-profitable.c:11:14: the cost-model indicates that vectorization is not beneficial
-; CHECK: remark: vectorization-remarks-profitable.c:11:14: the cost-model indicates that interleaving is not beneficial
+; CHECK: remark: vectorization-remarks-profitable.c:5:17: the cost-model indicates that vectorization is not beneficial
+; CHECK: remark: vectorization-remarks-profitable.c:5:17: the cost-model indicates that interleaving is not beneficial and is explicitly disabled or interleave count is set to 1
+; CHECK: remark: vectorization-remarks-profitable.c:12:17: the cost-model indicates that vectorization is not beneficial
+; CHECK: remark: vectorization-remarks-profitable.c:12:17: the cost-model indicates that interleaving is not beneficial
 
 ; First loop.
 ;  #pragma clang loop interleave(disable) unroll(disable)
 ;  for(int i = 0; i < n; i++) {
-;    out[i] = in[i];
+;    out[i] = *in[i];
 ;  }
 
 ; Second loop.
 ;  #pragma clang loop unroll(disable)
 ;  for(int i = 0; i < n; i++) {
-;    out[i] = in[i];
+;    out[i] = *in[i];
 ;  }
 
+; ModuleID = 'vectorization-remarks-profitable.ll'
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.10.0"
 
-; Function Attrs: nounwind ssp uwtable
-define void @do_not_interleave(float* nocapture %out, float* nocapture readonly %in, i32 %n) #0 {
+; Function Attrs: nounwind uwtable
+define void @do_not_interleave(float** noalias nocapture readonly %in, float* noalias nocapture %out, i32 %size) #0 {
 entry:
-  %cmp.7 = icmp sgt i32 %n, 0, !dbg !3
-  br i1 %cmp.7, label %for.body.preheader, label %for.cond.cleanup, !dbg !8
+  %cmp.4 = icmp eq i32 %size, 0, !dbg !10
+  br i1 %cmp.4, label %for.end, label %for.body.preheader, !dbg !11
 
 for.body.preheader:                               ; preds = %entry
-  br label %for.body, !dbg !9
-
-for.cond.cleanup.loopexit:                        ; preds = %for.body
-  br label %for.cond.cleanup, !dbg !10
-
-for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
-  ret void, !dbg !10
+  br label %for.body, !dbg !12
 
 for.body:                                         ; preds = %for.body.preheader, %for.body
   %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %for.body.preheader ]
-  %arrayidx = getelementptr inbounds float, float* %in, i64 %indvars.iv, !dbg !9
-  %0 = bitcast float* %arrayidx to i32*, !dbg !9
-  %1 = load i32, i32* %0, align 4, !dbg !9, !tbaa !11
-  %arrayidx2 = getelementptr inbounds float, float* %out, i64 %indvars.iv, !dbg !15
-  %2 = bitcast float* %arrayidx2 to i32*, !dbg !16
-  store i32 %1, i32* %2, align 4, !dbg !16, !tbaa !11
-  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1, !dbg !8
-  %lftr.wideiv = trunc i64 %indvars.iv.next to i32, !dbg !8
-  %exitcond = icmp eq i32 %lftr.wideiv, %n, !dbg !8
-  br i1 %exitcond, label %for.cond.cleanup.loopexit, label %for.body, !dbg !8, !llvm.loop !17
+  %arrayidx = getelementptr inbounds float*, float** %in, i64 %indvars.iv, !dbg !12
+  %0 = bitcast float** %arrayidx to i32**, !dbg !12
+  %1 = load i32*, i32** %0, align 8, !dbg !12
+  %2 = load i32, i32* %1, align 4, !dbg !13
+  %arrayidx2 = getelementptr inbounds float, float* %out, i64 %indvars.iv, !dbg !14
+  %3 = bitcast float* %arrayidx2 to i32*, !dbg !15
+  store i32 %2, i32* %3, align 4, !dbg !15
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1, !dbg !11
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32, !dbg !11
+  %exitcond = icmp eq i32 %lftr.wideiv, %size, !dbg !11
+  br i1 %exitcond, label %for.end.loopexit, label %for.body, !dbg !11, !llvm.loop !16
+
+for.end.loopexit:                                 ; preds = %for.body
+  br label %for.end, !dbg !19
+
+for.end:                                          ; preds = %for.end.loopexit, %entry
+  ret void, !dbg !19
 }
 
-; Function Attrs: nounwind ssp uwtable
-define void @interleave_not_profitable(float* nocapture %out, float* nocapture readonly %in, i32 %n) #0 {
+; Function Attrs: nounwind uwtable
+define void @interleave_not_profitable(float** noalias nocapture readonly %in, float* noalias nocapture %out, i32 %size) #0 {
 entry:
-  %cmp.7 = icmp sgt i32 %n, 0, !dbg !20
-  br i1 %cmp.7, label %for.body.preheader, label %for.cond.cleanup, !dbg !22
-
-for.body.preheader:                               ; preds = %entry
-  br label %for.body, !dbg !23
-
-for.cond.cleanup.loopexit:                        ; preds = %for.body
-  br label %for.cond.cleanup, !dbg !24
-
-for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
-  ret void, !dbg !24
-
-for.body:                                         ; preds = %for.body.preheader, %for.body
-  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %for.body.preheader ]
-  %arrayidx = getelementptr inbounds float, float* %in, i64 %indvars.iv, !dbg !23
-  %0 = bitcast float* %arrayidx to i32*, !dbg !23
-  %1 = load i32, i32* %0, align 4, !dbg !23, !tbaa !11
-  %arrayidx2 = getelementptr inbounds float, float* %out, i64 %indvars.iv, !dbg !25
-  %2 = bitcast float* %arrayidx2 to i32*, !dbg !26
-  store i32 %1, i32* %2, align 4, !dbg !26, !tbaa !11
-  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1, !dbg !22
-  %lftr.wideiv = trunc i64 %indvars.iv.next to i32, !dbg !22
-  %exitcond = icmp eq i32 %lftr.wideiv, %n, !dbg !22
-  br i1 %exitcond, label %for.cond.cleanup.loopexit, label %for.body, !dbg !22, !llvm.loop !27
+  %cmp.4 = icmp eq i32 %size, 0, !dbg !20
+  br i1 %cmp.4, label %for.end, label %for.body, !dbg !21
+
+for.body:                                         ; preds = %entry, %for.body
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds float*, float** %in, i64 %indvars.iv, !dbg !22
+  %0 = bitcast float** %arrayidx to i32**, !dbg !22
+  %1 = load i32*, i32** %0, align 8, !dbg !22
+  %2 = load i32, i32* %1, align 4, !dbg !23
+  %arrayidx2 = getelementptr inbounds float, float* %out, i64 %indvars.iv, !dbg !24
+  %3 = bitcast float* %arrayidx2 to i32*, !dbg !25
+  store i32 %2, i32* %3, align 4, !dbg !25
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1, !dbg !21
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32, !dbg !21
+  %exitcond = icmp eq i32 %lftr.wideiv, %size, !dbg !21
+  br i1 %exitcond, label %for.end, label %for.body, !dbg !21, !llvm.loop !26
+
+for.end:                                          ; preds = %for.body, %entry
+  ret void, !dbg !27
 }
 
-attributes #0 = { nounwind }
-
-!llvm.module.flags = !{!0, !1}
-!llvm.ident = !{!2}
-
-!0 = !{i32 2, !"Debug Info Version", i32 3}
-!1 = !{i32 1, !"PIC Level", i32 2}
-!2 = !{!"clang version 3.7.0"}
-!3 = !DILocation(line: 3, column: 20, scope: !4)
-!4 = distinct !DISubprogram(name: "do_not_interleave", scope: !5, file: !5, line: 1, type: !6, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, function: void (float*, float*, i32)* @do_not_interleave, variables: !7)
-!5 = !DIFile(filename: "vectorization-remarks-profitable.c", directory: "")
-!6 = !DISubroutineType(types: !7)
-!7 = !{}
-!8 = !DILocation(line: 3, column: 3, scope: !4)
-!9 = !DILocation(line: 4, column: 14, scope: !4)
-!10 = !DILocation(line: 6, column: 1, scope: !4)
-!11 = !{!12, !12, i64 0}
-!12 = !{!"float", !13, i64 0}
-!13 = !{!"omnipotent char", !14, i64 0}
-!14 = !{!"Simple C/C++ TBAA"}
-!15 = !DILocation(line: 4, column: 5, scope: !4)
-!16 = !DILocation(line: 4, column: 12, scope: !4)
-!17 = distinct !{!17, !18, !19}
-!18 = !{!"llvm.loop.interleave.count", i32 1}
-!19 = !{!"llvm.loop.unroll.disable"}
-!20 = !DILocation(line: 10, column: 20, scope: !21)
-!21 = distinct !DISubprogram(name: "interleave_not_profitable", scope: !5, file: !5, line: 8, type: !6, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: true, function: void (float*, float*, i32)* @interleave_not_profitable, variables: !7)
-!22 = !DILocation(line: 10, column: 3, scope: !21)
-!23 = !DILocation(line: 11, column: 14, scope: !21)
-!24 = !DILocation(line: 13, column: 1, scope: !21)
-!25 = !DILocation(line: 11, column: 5, scope: !21)
-!26 = !DILocation(line: 11, column: 12, scope: !21)
-!27 = distinct !{!27, !19}
+attributes #0 = { nounwind uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!7, !8}
+!llvm.ident = !{!9}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.8.0 (trunk 250016)", isOptimized: false, runtimeVersion: 0, emissionKind: 2, enums: !2, subprograms: !3)
+!1 = !DIFile(filename: "vectorization-remarks-profitable.c", directory: "")
+!2 = !{}
+!3 = !{!4, !6}
+!4 = distinct !DISubprogram(name: "do_not_interleave", scope: !1, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, function: void (float**, float*, i32)* @do_not_interleave, variables: !2)
+!5 = !DISubroutineType(types: !2)
+!6 = distinct !DISubprogram(name: "interleave_not_profitable", scope: !1, file: !1, line: 8, type: !5, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, function: void (float**, float*, i32)* @interleave_not_profitable, variables: !2)
+!7 = !{i32 2, !"Dwarf Version", i32 4}
+!8 = !{i32 2, !"Debug Info Version", i32 3}
+!9 = !{!"clang version 3.8.0 (trunk 250016)"}
+!10 = !DILocation(line: 4, column: 23, scope: !4)
+!11 = !DILocation(line: 4, column: 3, scope: !4)
+!12 = !DILocation(line: 5, column: 17, scope: !4)
+!13 = !DILocation(line: 5, column: 16, scope: !4)
+!14 = !DILocation(line: 5, column: 7, scope: !4)
+!15 = !DILocation(line: 5, column: 14, scope: !4)
+!16 = distinct !{!16, !17, !18}
+!17 = !{!"llvm.loop.interleave.count", i32 1}
+!18 = !{!"llvm.loop.unroll.disable"}
+!19 = !DILocation(line: 6, column: 1, scope: !4)
+!20 = !DILocation(line: 11, column: 23, scope: !6)
+!21 = !DILocation(line: 11, column: 3, scope: !6)
+!22 = !DILocation(line: 12, column: 17, scope: !6)
+!23 = !DILocation(line: 12, column: 16, scope: !6)
+!24 = !DILocation(line: 12, column: 7, scope: !6)
+!25 = !DILocation(line: 12, column: 14, scope: !6)
+!26 = distinct !{!26, !18}
+!27 = !DILocation(line: 13, column: 1, scope: !6)
+

diff --git a/test/Transforms/LoopVectorize/gep_with_bitcast.ll b/test/Transforms/LoopVectorize/gep_with_bitcast.ll
new file mode 100644 (file)
index 0000000..ab2fd5e
--- /dev/null
+++ b/test/Transforms/LoopVectorize/gep_with_bitcast.ll
@@ -0,0 +1,40 @@
+; RUN: opt -S -loop-vectorize -instcombine -force-vector-width=4  < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-i128:128-n32:64-S128"
+
+; Vectorization of loop with bitcast between GEP and load
+; Simplified source code:
+;void foo (double** __restrict__  in, bool * __restrict__ res) {
+;
+;  for (int i = 0; i < 4096; ++i)
+;    res[i] = ((unsigned long long)in[i] == 0);
+;}
+
+; CHECK-LABEL: @foo
+; CHECK: vector.body
+; CHECK:  %0 = getelementptr inbounds double*, double** %in, i64 %index
+; CHECK:  %1 = bitcast double** %0 to <4 x i64>*
+; CHECK:  %wide.load = load <4 x i64>, <4 x i64>* %1, align 8
+; CHECK:  %2 = icmp eq <4 x i64> %wide.load, zeroinitializer
+; CHECK:  br i1
+
+define void @foo(double** noalias nocapture readonly %in, double** noalias nocapture readnone %out, i8* noalias nocapture %res) #0 {
+entry:
+  br label %for.body
+
+for.body:
+  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+  %arrayidx = getelementptr inbounds double*, double** %in, i64 %indvars.iv
+  %tmp53 = bitcast double** %arrayidx to i64*
+  %tmp54 = load i64, i64* %tmp53, align 8
+  %cmp1 = icmp eq i64 %tmp54, 0
+  %arrayidx3 = getelementptr inbounds i8, i8* %res, i64 %indvars.iv
+  %frombool = zext i1 %cmp1 to i8
+  store i8 %frombool, i8* %arrayidx3, align 1
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, 4096
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
+}
\ No newline at end of file