Teach LowerBRCOND to recognize (xor (setcc x), 1). The xor inverts the condition. It's normally transformed by the dag combiner, unless the condition is set by a arithmetic op with overflow.

llvm-svn: 63505

1 files changed, 23 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/smul-with-overflow-3.ll b/llvm/test/CodeGen/X86/smul-with-overflow-3.ll
new file mode 100644
index 00000000000..aa5e67a0299
--- /dev/null
+++ b/llvm/test/CodeGen/X86/smul-with-overflow-3.ll
@@ -0,0 +1,23 @@
+; RUN: llvm-as < %s | llc -march=x86 | grep {jno} | count 1
+
+@ok = internal constant [4 x i8] c"%d\0A\00"
+@no = internal constant [4 x i8] c"no\0A\00"
+
+define i1 @func1(i32 %v1, i32 %v2) nounwind {
+entry:
+  %t = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %v1, i32 %v2)
+  %sum = extractvalue {i32, i1} %t, 0
+  %obit = extractvalue {i32, i1} %t, 1
+  br i1 %obit, label %overflow, label %normal
+
+overflow:
+  %t2 = tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @no, i32 0, i32 0) ) nounwind
+  ret i1 false
+
+normal:
+  %t1 = tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @ok, i32 0, i32 0), i32 %sum ) nounwind
+  ret i1 true
+}
+
+declare i32 @printf(i8*, ...) nounwind
+declare {i32, i1} @llvm.smul.with.overflow.i32(i32, i32)