[EarlyCSE] Don't hide earler invariant.scopes
If we've already established an invariant scope with an earlier generation, we don't want to hide it in the scoped hash table with one with a later generation. I noticed this when working on the invariant-load handling, but it also applies to the invariant.start case as well.
Without this change, my previous patch for invariant-load regresses some cases, so I'm pushing this without waiting for review. This is why you don't make last minute tweaks to patches to catch "obvious cases" after it's already been reviewed. Bad Philip!
llvm-svn: 327655
diff --git a/llvm/test/Transforms/EarlyCSE/invariant-loads.ll b/llvm/test/Transforms/EarlyCSE/invariant-loads.ll
index 889e6cb..c3fa32d 100644
--- a/llvm/test/Transforms/EarlyCSE/invariant-loads.ll
+++ b/llvm/test/Transforms/EarlyCSE/invariant-loads.ll
@@ -135,3 +135,24 @@
call void @clobber_and_use(i32 %v3)
ret void
}
+
+; If we already have an invariant scope, don't want to start a new one
+; with a potentially greater generation. This hides the earlier invariant
+; load
+define void @test_scope_restart(i32* %p) {
+; CHECK-LABEL: @test_scope_restart
+; CHECK: %v1 = load i32, i32* %p
+; CHECK: call void @clobber_and_use(i32 %v1)
+; CHECK: %add = add i32 %v1, %v1
+; CHECK: call void @clobber_and_use(i32 %add)
+; CHECK: call void @clobber_and_use(i32 %v1)
+; CHECK: ret void
+ %v1 = load i32, i32* %p, !invariant.load !{}
+ call void @clobber_and_use(i32 %v1)
+ %v2 = load i32, i32* %p, !invariant.load !{}
+ %add = add i32 %v1, %v2
+ call void @clobber_and_use(i32 %add)
+ %v3 = load i32, i32* %p
+ call void @clobber_and_use(i32 %v3)
+ ret void
+}
diff --git a/llvm/test/Transforms/EarlyCSE/invariant.start.ll b/llvm/test/Transforms/EarlyCSE/invariant.start.ll
index 5fabd0c..b5dc9a6 100644
--- a/llvm/test/Transforms/EarlyCSE/invariant.start.ll
+++ b/llvm/test/Transforms/EarlyCSE/invariant.start.ll
@@ -93,6 +93,18 @@
ret i32 %sub
}
+define i32 @test_duplicate_scope(i32* %p) {
+; CHECK-LABEL: @test_duplicate_scope
+; CHECK: ret i32 0
+ %v1 = load i32, i32* %p
+ call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
+ call void @clobber()
+ call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
+ %v2 = load i32, i32* %p
+ %sub = sub i32 %v1, %v2
+ ret i32 %sub
+}
+
define i32 @test_unanalzyable_load(i32* %p) {
; CHECK-LABEL: @test_unanalzyable_load
; CHECK: ret i32 0