[CodeGenPrepare] Handle properly the promotion of operands when this does not

generate instructions.

Fixes PR21978.
Related to <rdar://problem/18310086>

llvm-svn: 224717

1 files changed, 25 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/codegen-prepare-extload.ll b/llvm/test/CodeGen/X86/codegen-prepare-extload.ll
index f607a6f3569..9b27c33a80f 100644
--- a/llvm/test/CodeGen/X86/codegen-prepare-extload.ll
+++ b/llvm/test/CodeGen/X86/codegen-prepare-extload.ll
@@ -336,3 +336,28 @@ entry:
   %b = zext <2 x i32> %a to <2 x i64>
   ret void
 }
+
+@a = common global i32 0, align 4
+@c = common global [2 x i32] zeroinitializer, align 4
+
+; PR21978.
+; Make sure we support promotion of operands that produces a Value as opposed
+; to an instruction.
+; This used to cause a crash.
+; OPTALL-LABEL: @promotionOfArgEndsUpInValue
+; OPTALL: [[LD:%[a-zA-Z_0-9-]+]] = load i16* %addr
+
+; OPT-NEXT: [[SEXT:%[a-zA-Z_0-9-]+]] = sext i16 [[LD]] to i32
+; OPT-NEXT: [[RES:%[a-zA-Z_0-9-]+]] = add nuw nsw i32 [[SEXT]], zext (i1 icmp ne (i32* getelementptr inbounds ([2 x i32]* @c, i64 0, i64 1), i32* @a) to i32)
+;
+; DISABLE-NEXT: [[ADD:%[a-zA-Z_0-9-]+]] = add nuw nsw i16 [[LD]], zext (i1 icmp ne (i32* getelementptr inbounds ([2 x i32]* @c, i64 0, i64 1), i32* @a) to i16)
+; DISABLE-NEXT: [[RES:%[a-zA-Z_0-9-]+]] = sext i16 [[ADD]] to i32
+;
+; OPTALL-NEXT: ret i32 [[RES]]
+define i32 @promotionOfArgEndsUpInValue(i16* %addr) {
+entry:
+  %val = load i16* %addr
+  %add = add nuw nsw i16 %val, zext (i1 icmp ne (i32* getelementptr inbounds ([2 x i32]* @c, i64 0, i64 1), i32* @a) to i16)
+  %conv3 = sext i16 %add to i32
+  ret i32 %conv3
+}