Teach instcombine all sorts of great stuff about shifts that have exact, nuw or

nsw bits on them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147528 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 54 insertions, 0 deletions

diff --git a/test/Transforms/InstCombine/shift.ll b/test/Transforms/InstCombine/shift.ll
index 0dd969b8c0..52310e34e0 100644
--- a/test/Transforms/InstCombine/shift.ll
+++ b/test/Transforms/InstCombine/shift.ll
@@ -560,3 +560,57 @@ define i32 @test47(i32 %a) {
 ; CHECK-NEXT: %z = lshr exact i32 %a, 2
 ; CHECK-NEXT: ret i32 %z
 }
+
+define i32 @test48(i32 %x) {
+  %A = lshr exact i32 %x, 1
+  %B = shl i32 %A, 3
+  ret i32 %B
+; CHECK: @test48
+; CHECK-NEXT: %B = shl i32 %x, 2
+; CHECK-NEXT: ret i32 %B
+}
+
+define i32 @test49(i32 %x) {
+  %A = ashr exact i32 %x, 1
+  %B = shl i32 %A, 3
+  ret i32 %B
+; CHECK: @test49
+; CHECK-NEXT: %B = shl i32 %x, 2
+; CHECK-NEXT: ret i32 %B
+}
+
+define i32 @test50(i32 %x) {
+  %A = shl nsw i32 %x, 1
+  %B = ashr i32 %A, 3
+  ret i32 %B
+; CHECK: @test50
+; CHECK-NEXT: %B = ashr i32 %x, 2
+; CHECK-NEXT: ret i32 %B
+}
+
+define i32 @test51(i32 %x) {
+  %A = shl nuw i32 %x, 1
+  %B = lshr i32 %A, 3
+  ret i32 %B
+; CHECK: @test51
+; CHECK-NEXT: %B = lshr i32 %x, 2
+; CHECK-NEXT: ret i32 %B
+}
+
+define i32 @test52(i32 %x) {
+  %A = shl nsw i32 %x, 3
+  %B = ashr i32 %A, 1
+  ret i32 %B
+; CHECK: @test52
+; CHECK-NEXT: %B = shl nsw i32 %x, 2
+; CHECK-NEXT: ret i32 %B
+}
+
+define i32 @test53(i32 %x) {
+  %A = shl nuw i32 %x, 3
+  %B = lshr i32 %A, 1
+  ret i32 %B
+; CHECK: @test53
+; CHECK-NEXT: %B = shl nuw i32 %x, 2
+; CHECK-NEXT: ret i32 %B
+}