Arithmetic instructions don't set EFLAGS bits OF and CF bits

[oota-llvm.git] / test / CodeGen / X86 / peep-test-2.ll

diff --git a/test/CodeGen/X86/peep-test-2.ll b/test/CodeGen/X86/peep-test-2.ll
new file mode 100644 (file)
index 0000000..788f610
--- /dev/null
+++ b/test/CodeGen/X86/peep-test-2.ll
@@ -0,0 +1,17 @@
+; RUN: llvm-as < %s | llc -march=x86 | grep testl
+
+; It's tempting to eliminate the testl instruction here and just use the
+; EFLAGS value from the incl, however it can't be known whether the add
+; will overflow, and if it does the incl would set OF, and the
+; subsequent setg would return true.
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+target triple = "i386-apple-darwin9.6"
+
+define i32 @f(i32 %j) nounwind readnone {
+entry:
+       %0 = add i32 %j, 1              ; <i32> [#uses=1]
+       %1 = icmp sgt i32 %0, 0         ; <i1> [#uses=1]
+       %2 = zext i1 %1 to i32          ; <i32> [#uses=1]
+       ret i32 %2
+}