[RS4GC] Better codegen for deoptimize calls

Don't emit a gc.result for a statepoint lowered from
@llvm.experimental.deoptimize since the call into __llvm_deoptimize is
effectively noreturn.  Instead follow the corresponding gc.statepoint
with an "unreachable".

llvm-svn: 265485
diff --git a/llvm/test/Transforms/RewriteStatepointsForGC/deopt-intrinsic.ll b/llvm/test/Transforms/RewriteStatepointsForGC/deopt-intrinsic.ll
index 9a8f58c..ef0e2bd 100644
--- a/llvm/test/Transforms/RewriteStatepointsForGC/deopt-intrinsic.ll
+++ b/llvm/test/Transforms/RewriteStatepointsForGC/deopt-intrinsic.ll
@@ -4,10 +4,12 @@
 target triple = "x86_64-apple-macosx10.11.0"
 
 declare i32 @llvm.experimental.deoptimize.i32(...)
+declare void @llvm.experimental.deoptimize.isVoid(...)
 
 define i32 @caller_0(i32 addrspace(1)* %ptr) gc "statepoint-example" {
 ; CHECK-LABEL: @caller_0(
-; CHECK: @llvm.experimental.gc.statepoint.p0f_i32f(i64 2882400000, i32 0, i32 ()* @__llvm_deoptimize, i32 0
+; CHECK: @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @__llvm_deoptimize, i32 0
+; CHECK: unreachable
 entry:
   %v = call i32(...) @llvm.experimental.deoptimize.i32() [ "deopt"(i32 0, i32 addrspace(1)* %ptr) ]
   ret i32 %v
@@ -16,8 +18,18 @@
 
 define i32 @caller_1(i32 addrspace(1)* %ptr) gc "statepoint-example" {
 ; CHECK-LABEL: @caller_1
-; CHECK: @llvm.experimental.gc.statepoint.p0f_i32i32p1i32f(i64 2882400000, i32 0, i32 (i32, i32 addrspace(1)*)* bitcast (i32 ()* @__llvm_deoptimize to i32 (i32, i32 addrspace(1)*)*), i32 2, i32 0, i32 50, i32 addrspace(1)* %ptr
+; CHECK: @llvm.experimental.gc.statepoint.p0f_isVoidi32p1i32f(i64 2882400000, i32 0, void (i32, i32 addrspace(1)*)* bitcast (void ()* @__llvm_deoptimize to void (i32, i32 addrspace(1)*)*), i32 2, i32 0, i32 50, i32 addrspace(1)* %ptr
+; CHECK: unreachable
 entry:
   %v = call i32(...) @llvm.experimental.deoptimize.i32(i32 50, i32 addrspace(1)* %ptr) [ "deopt"(i32 0) ]
   ret i32 %v
 }
+
+define void @caller_2(i32 addrspace(1)* %ptr) gc "statepoint-example" {
+; CHECK-LABEL: @caller_2(
+; CHECK: @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* @__llvm_deoptimize, i32 0
+; CHECK: unreachable
+entry:
+  call void(...) @llvm.experimental.deoptimize.isVoid() [ "deopt"(i32 0, i32 addrspace(1)* %ptr) ]
+  ret void
+}