Minor optimization. sign-ext/anyext of undef is still undef.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127598 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 19 insertions, 5 deletions

diff --git a/test/CodeGen/ARM/shifter_operand.ll b/test/CodeGen/ARM/shifter_operand.ll
index 01e3a92..be891bc 100644
--- a/test/CodeGen/ARM/shifter_operand.ll
+++ b/test/CodeGen/ARM/shifter_operand.ll
@@ -51,19 +51,19 @@ entry:
 
 declare i8* @malloc(...)
 
-define fastcc void @test4() nounwind {
+define fastcc void @test4(i16 %addr) nounwind {
 entry:
 ; A8: test4:
-; A8: ldr r1, [r0, r0, lsl #2]
-; A8: str r1, [r0, r0, lsl #2]
+; A8: ldr r2, [r0, r1, lsl #2]
+; A8: str r2, [r0, r1, lsl #2]
 
 ; A9: test4:
-; A9: add r0, r0, r0, lsl #2
+; A9: add r0, r0, r4, lsl #2
 ; A9: ldr r1, [r0]
 ; A9: str r1, [r0]
   %0 = tail call i8* (...)* @malloc(i32 undef) nounwind
   %1 = bitcast i8* %0 to i32*
-  %2 = sext i16 undef to i32
+  %2 = sext i16 %addr to i32
   %3 = getelementptr inbounds i32* %1, i32 %2
   %4 = load i32* %3, align 4
   %5 = add nsw i32 %4, 1
diff --git a/test/CodeGen/ARM/undef-sext.ll b/test/CodeGen/ARM/undef-sext.ll
new file mode 100644
index 0000000..2c28da3
--- /dev/null
+++ b/test/CodeGen/ARM/undef-sext.ll
@@ -0,0 +1,14 @@
+; RUN: llc < %s -mtriple=armv7-apple-darwin -mcpu=cortex-a8 | FileCheck %s
+
+; No need to sign-extend undef.
+
+define i32 @t(i32* %a) nounwind {
+entry:
+; CHECK: t:
+; CHECK: ldr r0, [r0]
+; CHECK: bx lr
+  %0 = sext i16 undef to i32
+  %1 = getelementptr inbounds i32* %a, i32 %0
+  %2 = load i32* %1, align 4
+  ret i32 %2
+}