[GuardWidening] Ignore guards with trivial conditions
Guard widening should not spend efforts on dealing with guards with trivial true/false conditions.
Such guards can easily be eliminated by any further cleanup pass like instcombine. However we
should not unconditionally delete them because it may be profitable to widen other conditions
into such guards.
Differential Revision: https://reviews.llvm.org/D50247
Reviewed By: fedor.sergeev
llvm-svn: 340381
diff --git a/llvm/test/Transforms/GuardWidening/basic.ll b/llvm/test/Transforms/GuardWidening/basic.ll
index 5b746a5..ab18ed7 100644
--- a/llvm/test/Transforms/GuardWidening/basic.ll
+++ b/llvm/test/Transforms/GuardWidening/basic.ll
@@ -379,3 +379,29 @@
right:
ret void
}
+
+; Make sure we do not widen guard by trivial true conditions into something.
+define void @f_15(i1 %cond_0, i1 %cond_1) {
+; CHECK-LABEL: @f_15(
+entry:
+; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
+; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 true) [ "deopt"() ]
+; CHECK: ret void
+
+ call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
+ call void(i1, ...) @llvm.experimental.guard(i1 true) [ "deopt"() ]
+ ret void
+}
+
+; Make sure we do not widen guard by trivial false conditions into something.
+define void @f_16(i1 %cond_0, i1 %cond_1) {
+; CHECK-LABEL: @f_16(
+entry:
+; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
+; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 false) [ "deopt"() ]
+; CHECK: ret void
+
+ call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
+ call void(i1, ...) @llvm.experimental.guard(i1 false) [ "deopt"() ]
+ ret void
+}