InstCombine: Make sure we use the pre-zext type when creating a constant of a value that is zext'd.

Fixes PR13250.

llvm-svn: 164377

2 files changed, 16 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index 2a7182fc1d4..3361a1e7fbe 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -477,7 +477,8 @@ Instruction *InstCombiner::visitUDiv(BinaryOperator &I) {
     if (match(Op1, m_Shl(m_Power2(CI), m_Value(N))) ||
         match(Op1, m_ZExt(m_Shl(m_Power2(CI), m_Value(N))))) {
       if (*CI != 1)
-        N = Builder->CreateAdd(N, ConstantInt::get(I.getType(),CI->logBase2()));
+        N = Builder->CreateAdd(N,
+                               ConstantInt::get(N->getType(), CI->logBase2()));
       if (ZExtInst *Z = dyn_cast<ZExtInst>(Op1))
         N = Builder->CreateZExt(N, Z->getDestTy());
       if (I.isExact())
diff --git a/llvm/test/Transforms/InstCombine/div-shift.ll b/llvm/test/Transforms/InstCombine/div-shift.ll
index a07f3ea9491..e0372ebac18 100644
--- a/llvm/test/Transforms/InstCombine/div-shift.ll
+++ b/llvm/test/Transforms/InstCombine/div-shift.ll
@@ -21,3 +21,17 @@ define i64 @t2(i64 %x, i32 %y) nounwind  {
   %3 = udiv i64 %x, %2
   ret i64 %3
 }
+
+; PR13250
+define i64 @t3(i64 %x, i32 %y) nounwind  {
+; CHECK: t3
+; CHECK-NOT: udiv
+; CHECK-NEXT: %1 = add i32 %y, 2
+; CHECK-NEXT: %2 = zext i32 %1 to i64
+; CHECK-NEXT: %3 = lshr i64 %x, %2
+; CHECK-NEXT: ret i64 %3
+  %1 = shl i32 4, %y
+  %2 = zext i32 %1 to i64
+  %3 = udiv i64 %x, %2
+  ret i64 %3
+}