[PATCH] Fix assert with GEP ptr vector indexing structs

Matt Arsenault Matthew.Arsenault at amd.com
Fri Aug 16 17:21:37 PDT 2013


Also fix it calculating the wrong value. The struct index is not a ConstantInt, so it was being interpreted as an array index.

http://llvm-reviews.chandlerc.com/D1431

Files:
  include/llvm/Transforms/Utils/Local.h
  lib/Analysis/ValueTracking.cpp
  test/Transforms/InstCombine/getelementptr.ll

Index: include/llvm/Transforms/Utils/Local.h
===================================================================
--- include/llvm/Transforms/Utils/Local.h
+++ include/llvm/Transforms/Utils/Local.h
@@ -203,12 +203,17 @@
        ++i, ++GTI) {
     Value *Op = *i;
     uint64_t Size = TD.getTypeAllocSize(GTI.getIndexedType()) & PtrSizeMask;
-    if (ConstantInt *OpC = dyn_cast<ConstantInt>(Op)) {
-      if (OpC->isZero()) continue;
+    if (Constant *OpC = dyn_cast<Constant>(Op)) {
+      if (OpC->isZeroValue())
+        continue;
+
+      if (OpC->getType()->isVectorTy())
+        OpC = OpC->getSplatValue();
 
       // Handle a struct index, which adds its field offset to the pointer.
       if (StructType *STy = dyn_cast<StructType>(*GTI)) {
-        Size = TD.getStructLayout(STy)->getElementOffset(OpC->getZExtValue());
+        uint64_t OpValue = cast<ConstantInt>(OpC)->getZExtValue();
+        Size = TD.getStructLayout(STy)->getElementOffset(OpValue);
 
         if (Size)
           Result = Builder->CreateAdd(Result, ConstantInt::get(IntPtrTy, Size),
Index: lib/Analysis/ValueTracking.cpp
===================================================================
--- lib/Analysis/ValueTracking.cpp
+++ lib/Analysis/ValueTracking.cpp
@@ -629,9 +629,19 @@
       Value *Index = I->getOperand(i);
       if (StructType *STy = dyn_cast<StructType>(*GTI)) {
         // Handle struct member offset arithmetic.
-        if (!TD) return;
-        const StructLayout *SL = TD->getStructLayout(STy);
+        if (!TD)
+          return;
+
+        // Handle case when index is vector zeroinitializer
+        Constant *CIndex = cast<Constant>(Index);
+        if (CIndex->isZeroValue())
+          continue;
+
+        if (CIndex->getType()->isVectorTy())
+          Index = CIndex->getSplatValue();
+
         unsigned Idx = cast<ConstantInt>(Index)->getZExtValue();
+        const StructLayout *SL = TD->getStructLayout(STy);
         uint64_t Offset = SL->getElementOffset(Idx);
         TrailZ = std::min<unsigned>(TrailZ,
                                     countTrailingZeros(Offset));
Index: test/Transforms/InstCombine/getelementptr.ll
===================================================================
--- test/Transforms/InstCombine/getelementptr.ll
+++ test/Transforms/InstCombine/getelementptr.ll
@@ -129,6 +129,17 @@
 ; CHECK:    %C = icmp eq i64 %X, -1
 }
 
+define <2 x i1> @test13_vector(<2 x i64> %X, <2 x %S*> %P) nounwind {
+; CHECK-LABEL: @test13_vector(
+; CHECK-NEXT: shl nuw <2 x i64> %X, <i64 2, i64 2>
+; CHECK-NEXT: add <2 x i64> %A.idx, <i64 4, i64 4>
+; CHECK-NEXT: icmp eq <2 x i64> %A.offs, zeroinitializer
+  %A = getelementptr inbounds <2 x %S*> %P, <2 x i64> zeroinitializer, <2 x i32> <i32 1, i32 1>, <2 x i64> %X
+  %B = getelementptr inbounds <2 x %S*> %P, <2 x i64> <i64 0, i64 0>, <2 x i32> <i32 0, i32 0>
+  %C = icmp eq <2 x i32*> %A, %B
+  ret <2 x i1> %C
+}
+
 define i1 @test13_i32(i32 %X, %S* %P) {
 ; CHECK-LABEL: @test13_i32(
 ; CHECK: %C = icmp eq i32 %X, -1
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