Introduce a @llvm.experimental.guard intrinsic

Summary:
As discussed on llvm-dev[1].

This change adds the basic boilerplate code around having this intrinsic
in LLVM:

 - Changes in Intrinsics.td, and the IR Verifier
 - A lowering pass to lower @llvm.experimental.guard to normal
   control flow
 - Inliner support

[1]: http://lists.llvm.org/pipermail/llvm-dev/2016-February/095523.html

Reviewers: reames, atrick, chandlerc, rnk, JosephTremoulet, echristo

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D18527

llvm-svn: 264976

1 files changed, 39 insertions, 0 deletions

diff --git a/llvm/test/Transforms/Inline/guard-intrinsic.ll b/llvm/test/Transforms/Inline/guard-intrinsic.ll
new file mode 100644
index 00000000000..76d683df6e9
--- /dev/null
+++ b/llvm/test/Transforms/Inline/guard-intrinsic.ll
@@ -0,0 +1,39 @@
+; RUN: opt -S -always-inline < %s | FileCheck %s
+
+declare void @llvm.experimental.guard(i1, ...)
+
+define i8 @callee(i1* %c_ptr) alwaysinline {
+  %c = load volatile i1, i1* %c_ptr
+  call void(i1, ...) @llvm.experimental.guard(i1 %c, i32 1) [ "deopt"(i32 1) ]
+  ret i8 5
+}
+
+define void @caller_0(i1* %c, i8* %ptr) {
+; CHECK-LABEL: @caller_0(
+entry:
+; CHECK:  [[COND:%[^ ]+]] = load volatile i1, i1* %c
+; CHECK-NEXT:  call void (i1, ...) @llvm.experimental.guard(i1 [[COND]], i32 1) [ "deopt"(i32 2, i32 1) ]
+; CHECK-NEXT:  store i8 5, i8* %ptr
+
+  %v = call i8 @callee(i1* %c)  [ "deopt"(i32 2) ]
+  store i8 %v, i8* %ptr
+  ret void
+}
+
+define i32 @caller_1(i1* %c, i8* %ptr) personality i8 3 {
+; CHECK-LABEL: @caller_1(
+; CHECK:  [[COND:%[^ ]+]] = load volatile i1, i1* %c
+; CHECK-NEXT:  call void (i1, ...) @llvm.experimental.guard(i1 [[COND]], i32 1) [ "deopt"(i32 3, i32 1) ]
+; CHECK-NEXT:  br label %normal
+entry:
+  %v = invoke i8 @callee(i1* %c)  [ "deopt"(i32 3) ] to label %normal
+       unwind label %unwind
+
+unwind:
+  %lp = landingpad i32 cleanup
+  ret i32 43
+
+normal:
+  store i8 %v, i8* %ptr
+  ret i32 42
+}