[MemorySSA] Fix invariant.group test and add new

[Prazek]

Summary

This test had a bug: !llvm.invariant.group instead
of !invariant.group.

Also add some new test for future development.
All tests passes, when MSSA will support invariant.group
only the lines with FIXIT should be changed.

[george.burgess.iv]

So the idea is that we'll just use the dominating Def/Phi of the closest related barrier call for invariant group things?

Assuming yes, this LGTM. Thanks!

[Prazek]

In D28969#651997, @george.burgess.iv wrote:

So the idea is that we'll just use the dominating Def/Phi of the closest related barrier call for invariant group things?

Assuming yes, this LGTM. Thanks!

Yes, exactly. I am working on that now

llvm/trunk/test/Transforms/Util/MemorySSA/invariant-groups.ll

 ; RUN: opt -basicaa -print-memoryssa -verify-memoryssa -analyze < %s 2>&1 | FileCheck %s
 ;
 ; Currently, MemorySSA doesn't support invariant groups. So, we should ignore
 ; invariant.group.barrier intrinsics entirely. We'll need to pay attention to
 ; them when/if we decide to support invariant groups.
 
 @g = external global i32
 
 define i32 @foo(i32* %a) {
 ; CHECK: 1 = MemoryDef(liveOnEntry)
 ; CHECK-NEXT: store i32 0
-  store i32 0, i32* %a, align 4, !llvm.invariant.group !0
+  store i32 0, i32* %a, align 4, !invariant.group !0
 
 ; CHECK: 2 = MemoryDef(1)
 ; CHECK-NEXT: store i32 1
   store i32 1, i32* @g, align 4
 
   %1 = bitcast i32* %a to i8*
   %a8 = call i8* @llvm.invariant.group.barrier(i8* %1)
   %a32 = bitcast i8* %a8 to i32*
 
+; This have to be MemoryUse(1), because we can't skip the barrier based on
+; invariant.group.
 ; CHECK: MemoryUse(2)
 ; CHECK-NEXT: %2 = load i32
-  %2 = load i32, i32* %a32, align 4, !llvm.invariant.group !0
+  %2 = load i32, i32* %a32, align 4, !invariant.group !0
   ret i32 %2
 }
 
+define i32 @skipBarrier(i32* %a) {
+; CHECK: 1 = MemoryDef(liveOnEntry)
+; CHECK-NEXT: store i32 0
+  store i32 0, i32* %a, align 4, !invariant.group !0
+
+  %1 = bitcast i32* %a to i8*
+  %a8 = call i8* @llvm.invariant.group.barrier(i8* %1)
+  %a32 = bitcast i8* %a8 to i32*
+
+; We can skip the barrier only if the "skip" is not based on !invariant.group.
+; CHECK: MemoryUse(1)
+; CHECK-NEXT: %2 = load i32
+  %2 = load i32, i32* %a32, align 4, !invariant.group !0
+  ret i32 %2
+}
+
+define i32 @skipBarrier2(i32* %a) {
+
+; CHECK: MemoryUse(liveOnEntry)
+; CHECK-NEXT: %v = load i32
+  %v = load i32, i32* %a, align 4, !invariant.group !0
+
+  %1 = bitcast i32* %a to i8*
+  %a8 = call i8* @llvm.invariant.group.barrier(i8* %1)
+  %a32 = bitcast i8* %a8 to i32*
+
+; We can skip the barrier only if the "skip" is not based on !invariant.group.
+; CHECK: MemoryUse(liveOnEntry)
+; CHECK-NEXT: %v2 = load i32
+  %v2 = load i32, i32* %a32, align 4, !invariant.group !0
+; CHECK: 1 = MemoryDef(liveOnEntry)
+; CHECK-NEXT: store i32 1
+  store i32 1, i32* @g, align 4
+
+; FIXME: based on invariant.group it should be MemoryUse(liveOnEntry)
+; CHECK: MemoryUse(1)
+; CHECK-NEXT: %v3 = load i32
+  %v3 = load i32, i32* %a32, align 4, !invariant.group !0
+  %add = add nsw i32 %v2, %v3
+  %add2 = add nsw i32 %add, %v
+  ret i32 %add2
+}
+
+define i32 @handleInvariantGroups(i32* %a) {
+; CHECK: 1 = MemoryDef(liveOnEntry)
+; CHECK-NEXT: store i32 0
+  store i32 0, i32* %a, align 4, !invariant.group !0
+
+; CHECK: 2 = MemoryDef(1)
+; CHECK-NEXT: store i32 1
+  store i32 1, i32* @g, align 4
+  %1 = bitcast i32* %a to i8*
+  %a8 = call i8* @llvm.invariant.group.barrier(i8* %1)
+  %a32 = bitcast i8* %a8 to i32*
+
+; CHECK: MemoryUse(2)
+; CHECK-NEXT: %2 = load i32
+  %2 = load i32, i32* %a32, align 4, !invariant.group !0
+
+; CHECK: 3 = MemoryDef(2)
+; CHECK-NEXT: store i32 2
+  store i32 2, i32* @g, align 4
+
+; FIXME: This can be changed to MemoryUse(2)
+; CHECK: MemoryUse(3)
+; CHECK-NEXT: %3 = load i32
+  %3 = load i32, i32* %a32, align 4, !invariant.group !0
+  %add = add nsw i32 %2, %3
+  ret i32 %add
+}
+
 declare i8* @llvm.invariant.group.barrier(i8*)
 
 !0 = !{!"group1"}