MemCpyOpt: When forming a memset from stores also take GEP constexprs into account.

This is common when storing to global variables.

llvm-svn: 163809

2 files changed, 27 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
index 2a5ee33eb1e..35acc792387 100644
--- a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
+++ b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
@@ -38,7 +38,7 @@ STATISTIC(NumMemSetInfer, "Number of memsets inferred");
 STATISTIC(NumMoveToCpy,   "Number of memmoves converted to memcpy");
 STATISTIC(NumCpyToSet,    "Number of memcpys converted to memset");
 
-static int64_t GetOffsetFromIndex(const GetElementPtrInst *GEP, unsigned Idx,
+static int64_t GetOffsetFromIndex(const GEPOperator *GEP, unsigned Idx,
                                   bool &VariableIdxFound, const TargetData &TD){
   // Skip over the first indices.
   gep_type_iterator GTI = gep_type_begin(GEP);
@@ -75,8 +75,8 @@ static bool IsPointerOffset(Value *Ptr1, Value *Ptr2, int64_t &Offset,
                             const TargetData &TD) {
   Ptr1 = Ptr1->stripPointerCasts();
   Ptr2 = Ptr2->stripPointerCasts();
-  GetElementPtrInst *GEP1 = dyn_cast<GetElementPtrInst>(Ptr1);
-  GetElementPtrInst *GEP2 = dyn_cast<GetElementPtrInst>(Ptr2);
+  GEPOperator *GEP1 = dyn_cast<GEPOperator>(Ptr1);
+  GEPOperator *GEP2 = dyn_cast<GEPOperator>(Ptr2);
 
   bool VariableIdxFound = false;
 
diff --git a/llvm/test/Transforms/MemCpyOpt/form-memset.ll b/llvm/test/Transforms/MemCpyOpt/form-memset.ll
index 8832f897b08..f63b1dcfdd5 100644
--- a/llvm/test/Transforms/MemCpyOpt/form-memset.ll
+++ b/llvm/test/Transforms/MemCpyOpt/form-memset.ll
@@ -248,3 +248,27 @@ entry:
 ; CHECK: @test8
 ; CHECK: store <4 x i32> <i32 -1, i32 -1, i32 -1, i32 -1>, <4 x i32>* %0, align 16
 }
+
+@test9buf = internal unnamed_addr global [16 x i64] zeroinitializer, align 16
+
+define void @test9() nounwind {
+  store i8 -1, i8* bitcast ([16 x i64]* @test9buf to i8*), align 16
+  store i8 -1, i8* getelementptr (i8* bitcast ([16 x i64]* @test9buf to i8*), i64 1), align 1
+  store i8 -1, i8* getelementptr (i8* bitcast ([16 x i64]* @test9buf to i8*), i64 2), align 2
+  store i8 -1, i8* getelementptr (i8* bitcast ([16 x i64]* @test9buf to i8*), i64 3), align 1
+  store i8 -1, i8* getelementptr (i8* bitcast ([16 x i64]* @test9buf to i8*), i64 4), align 4
+  store i8 -1, i8* getelementptr (i8* bitcast ([16 x i64]* @test9buf to i8*), i64 5), align 1
+  store i8 -1, i8* getelementptr (i8* bitcast ([16 x i64]* @test9buf to i8*), i64 6), align 2
+  store i8 -1, i8* getelementptr (i8* bitcast ([16 x i64]* @test9buf to i8*), i64 7), align 1
+  store i8 -1, i8* bitcast (i64* getelementptr inbounds ([16 x i64]* @test9buf, i64 0, i64 1) to i8*), align 8
+  store i8 -1, i8* getelementptr (i8* bitcast ([16 x i64]* @test9buf to i8*), i64 9), align 1
+  store i8 -1, i8* getelementptr (i8* bitcast ([16 x i64]* @test9buf to i8*), i64 10), align 2
+  store i8 -1, i8* getelementptr (i8* bitcast ([16 x i64]* @test9buf to i8*), i64 11), align 1
+  store i8 -1, i8* getelementptr (i8* bitcast ([16 x i64]* @test9buf to i8*), i64 12), align 4
+  store i8 -1, i8* getelementptr (i8* bitcast ([16 x i64]* @test9buf to i8*), i64 13), align 1
+  store i8 -1, i8* getelementptr (i8* bitcast ([16 x i64]* @test9buf to i8*), i64 14), align 2
+  store i8 -1, i8* getelementptr (i8* bitcast ([16 x i64]* @test9buf to i8*), i64 15), align 1
+  ret void
+; CHECK: @test9(
+; CHECK: call void @llvm.memset.p0i8.i64(i8* bitcast ([16 x i64]* @test9buf to i8*), i8 -1, i64 16, i32 16, i1 false)
+}