x86: preserve flags when folding atomic operations

[oota-llvm.git] / test / CodeGen / X86 / atomic-flags.ll

diff --git a/test/CodeGen/X86/atomic-flags.ll b/test/CodeGen/X86/atomic-flags.ll
index 141a7690dba2004cb7aac32e3767d2d82f395ca4..e0c4a915965c8bafbb5def08d5730d133dd8d97e 100644 (file)
--- a/test/CodeGen/X86/atomic-flags.ll
+++ b/test/CodeGen/X86/atomic-flags.ll
@@ -3,8 +3,8 @@
 
 ; Make sure that flags are properly preserved despite atomic optimizations.
 
-define i32 @atomic_and_flags(i8* %p, i32 %a, i32 %b) {
-; CHECK-LABEL: atomic_and_flags:
+define i32 @atomic_and_flags_1(i8* %p, i32 %a, i32 %b) {
+; CHECK-LABEL: atomic_and_flags_1:
 
   ; Generate flags value, and use it.
   ; CHECK:      cmpl
@@ -14,9 +14,9 @@ define i32 @atomic_and_flags(i8* %p, i32 %a, i32 %b) {
 
 L1:
   ; The following pattern will get folded.
-  ; CHECK: addb
+  ; CHECK: incb
   %1 = load atomic i8, i8* %p seq_cst, align 1
-  %2 = add i8 %1, 2
+  %2 = add i8 %1, 1 ; This forces the INC instruction to be generated.
   store atomic i8 %2, i8* %p release, align 1
 
   ; Use the comparison result again. We need to rematerialize the comparison
@@ -36,3 +36,26 @@ L3:
 L4:
   ret i32 4
 }
+
+; Same as above, but using 2 as immediate to avoid the INC instruction.
+define i32 @atomic_and_flags_2(i8* %p, i32 %a, i32 %b) {
+; CHECK-LABEL: atomic_and_flags_2:
+  ; CHECK:      cmpl
+  ; CHECK-NEXT: jne
+  %cmp = icmp eq i32 %a, %b
+  br i1 %cmp, label %L1, label %L2
+L1:
+  ; CHECK: addb
+  %1 = load atomic i8, i8* %p seq_cst, align 1
+  %2 = add i8 %1, 2
+  store atomic i8 %2, i8* %p release, align 1
+  ; CHECK-NEXT: cmpl
+  ; CHECK-NEXT: jne
+  br i1 %cmp, label %L3, label %L4
+L2:
+  ret i32 2
+L3:
+  ret i32 3
+L4:
+  ret i32 4
+}