Speculatively revert "DeadStoreElimination can now trim the size of a store if

[oota-llvm.git] / test / Transforms / EarlyCSE / basic.ll

diff --git a/test/Transforms/EarlyCSE/basic.ll b/test/Transforms/EarlyCSE/basic.ll
index d42f503fc64b1ce9f513f1c5b46a13a2aeaeb700..57b1697ff4debcd40eef5b7c84a4bc975337831b 100644 (file)
--- a/test/Transforms/EarlyCSE/basic.ll
+++ b/test/Transforms/EarlyCSE/basic.ll
@@ -6,16 +6,116 @@ define void @test1(i8 %V, i32 *%P) {
   %A = bitcast i64 42 to double  ;; dead
   %B = add i32 4, 19             ;; constant folds
   store i32 %B, i32* %P
-  
   ; CHECK-NEXT: store i32 23, i32* %P
   
   %C = zext i8 %V to i32
   %D = zext i8 %V to i32  ;; CSE
   volatile store i32 %C, i32* %P
   volatile store i32 %D, i32* %P
-  
   ; CHECK-NEXT: %C = zext i8 %V to i32
-  ; CHECK-NEXT: volatile store i32 %C
-  ; CHECK-NEXT: volatile store i32 %C
+  ; CHECK-NEXT: store volatile i32 %C
+  ; CHECK-NEXT: store volatile i32 %C
+  
+  %E = add i32 %C, %C
+  %F = add i32 %C, %C
+  volatile store i32 %E, i32* %P
+  volatile store i32 %F, i32* %P
+  ; CHECK-NEXT: %E = add i32 %C, %C
+  ; CHECK-NEXT: store volatile i32 %E
+  ; CHECK-NEXT: store volatile i32 %E
+
+  %G = add nuw i32 %C, %C         ;; not a CSE with E
+  volatile store i32 %G, i32* %P
+  ; CHECK-NEXT: %G = add nuw i32 %C, %C
+  ; CHECK-NEXT: store volatile i32 %G
+  ret void
+}
+
+
+;; Simple load value numbering.
+; CHECK: @test2
+define i32 @test2(i32 *%P) {
+  %V1 = load i32* %P
+  %V2 = load i32* %P
+  %Diff = sub i32 %V1, %V2
+  ret i32 %Diff
+  ; CHECK: ret i32 0
+}
+
+;; Cross block load value numbering.
+; CHECK: @test3
+define i32 @test3(i32 *%P, i1 %Cond) {
+  %V1 = load i32* %P
+  br i1 %Cond, label %T, label %F
+T:
+  store i32 4, i32* %P
+  ret i32 42
+F:
+  %V2 = load i32* %P
+  %Diff = sub i32 %V1, %V2
+  ret i32 %Diff
+  ; CHECK: F:
+  ; CHECK: ret i32 0
+}
+
+;; Cross block load value numbering stops when stores happen.
+; CHECK: @test4
+define i32 @test4(i32 *%P, i1 %Cond) {
+  %V1 = load i32* %P
+  br i1 %Cond, label %T, label %F
+T:
+  ret i32 42
+F:
+  ; Clobbers V1
+  store i32 42, i32* %P
+  
+  %V2 = load i32* %P
+  %Diff = sub i32 %V1, %V2
+  ret i32 %Diff
+  ; CHECK: F:
+  ; CHECK: ret i32 %Diff
+}
+
+declare i32 @func(i32 *%P) readonly
+
+;; Simple call CSE'ing.
+; CHECK: @test5
+define i32 @test5(i32 *%P) {
+  %V1 = call i32 @func(i32* %P)
+  %V2 = call i32 @func(i32* %P)
+  %Diff = sub i32 %V1, %V2
+  ret i32 %Diff
+  ; CHECK: ret i32 0
+}
+
+;; Trivial Store->load forwarding
+; CHECK: @test6
+define i32 @test6(i32 *%P) {
+  store i32 42, i32* %P
+  %V1 = load i32* %P
+  ret i32 %V1
+  ; CHECK: ret i32 42
+}
+
+;; Trivial dead store elimination.
+; CHECK: @test7
+define void @test7(i32 *%P) {
+  store i32 42, i32* %P
+  store i32 45, i32* %P
   ret void
+  ; CHECK-NEXT: store i32 45
+  ; CHECK-NEXT: ret void
+}
+
+;; Readnone functions aren't invalidated by stores.
+; CHECK: @test8
+define i32 @test8(i32 *%P) {
+  %V1 = call i32 @func(i32* %P) readnone
+  store i32 4, i32* %P
+  %V2 = call i32 @func(i32* %P) readnone
+  %Diff = sub i32 %V1, %V2
+  ret i32 %Diff
+  ; CHECK: ret i32 0
 }
+
+