Revert r251291, "Loop Vectorizer - skipping "bitcast" before GEP"

It causes miscompilation of llvm/lib/ExecutionEngine/Interpreter/Execution.cpp.
See also PR25324.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251436 91177308-0d34-0410-b5e6-96231b3b80d8

Author: chapuni

lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -254,19 +254,6 @@ static Type* ToVectorTy(Type *Scalar, unsigned VF) {
   return VectorType::get(Scalar, VF);
 }
 
-/// A helper function that returns GEP instruction and knows to skip
-/// 'bitcast'.
-static GetElementPtrInst *getGEPInstruction(Value *Ptr) {
-
-  if (isa<GetElementPtrInst>(Ptr))
-    return cast<GetElementPtrInst>(Ptr);
-
-  if (isa<BitCastInst>(Ptr) &&
-      isa<GetElementPtrInst>(cast<BitCastInst>(Ptr)->getOperand(0)))
-    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
@@ -1956,7 +1943,7 @@ int LoopVectorizationLegality::isConsecutivePtr(Value *Ptr) {
     return II.getConsecutiveDirection();
   }
 
-  GetElementPtrInst *Gep = getGEPInstruction(Ptr);
+  GetElementPtrInst *Gep = dyn_cast_or_null<GetElementPtrInst>(Ptr);
   if (!Gep)
     return 0;
 
@@ -2350,7 +2337,7 @@ void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr) {
   VectorParts &Entry = WidenMap.get(Instr);
 
   // Handle consecutive loads/stores.
-  GetElementPtrInst *Gep = getGEPInstruction(Ptr);
+  GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr);
   if (Gep && Legal->isInductionVariable(Gep->getPointerOperand())) {
     setDebugLocFromInst(Builder, Gep);
     Value *PtrOperand = Gep->getPointerOperand();
@@ -2410,7 +2397,7 @@ void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr) {
     // We don't want to update the value in the map as it might be used in
     // another expression. So don't use a reference type for "StoredVal".
     VectorParts StoredVal = getVectorValue(SI->getValueOperand());
-
+    
     for (unsigned Part = 0; Part < UF; ++Part) {
       // Calculate the pointer for the specific unroll-part.
       Value *PartPtr =

test/Transforms/LoopVectorize/X86/vectorization-remarks-profitable.ll

@@ -1,113 +1,114 @@
 ; 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: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
+; 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
 
 ; 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 uwtable
-define void @do_not_interleave(float** noalias nocapture readonly %in, float* noalias nocapture %out, i32 %size) #0 {
+; Function Attrs: nounwind ssp uwtable
+define void @do_not_interleave(float* nocapture %out, float* nocapture readonly %in, i32 %n) #0 {
 entry:
-  %cmp.4 = icmp eq i32 %size, 0, !dbg !10
-  br i1 %cmp.4, label %for.end, label %for.body.preheader, !dbg !11
+  %cmp.7 = icmp sgt i32 %n, 0, !dbg !3
+  br i1 %cmp.7, label %for.body.preheader, label %for.cond.cleanup, !dbg !8
 
 for.body.preheader:                               ; preds = %entry
-  br label %for.body, !dbg !12
+  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
 
 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 !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
+  %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
 }
 
-; Function Attrs: nounwind uwtable
-define void @interleave_not_profitable(float** noalias nocapture readonly %in, float* noalias nocapture %out, i32 %size) #0 {
+; Function Attrs: nounwind ssp uwtable
+define void @interleave_not_profitable(float* nocapture %out, float* nocapture readonly %in, i32 %n) #0 {
 entry:
-  %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
-}
+  %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
 
-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)
+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
+}
 
+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}