[llvm] [SROA] Allow `llvm.launder.invariant.group` intrinsic to be splittable (PR #72056)

[Nikita Popov via llvm-commits]

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@@ -79,6 +79,84 @@ define void @g() {
   ret void
 }
 
+define void @store_and_launder() {
+; CHECK-LABEL: @store_and_launder(
+; CHECK-NEXT:    ret void
+;
+  %valptr = alloca i32, align 4
+  store i32 0, ptr %valptr, align 4
+  %barr = call ptr @llvm.launder.invariant.group.p0(ptr %valptr)
+  ret void
+}
+
+define i32 @launder_and_load() {
+; CHECK-LABEL: @launder_and_load(
+; CHECK-NEXT:    ret i32 undef
+;
+  %valptr = alloca i32, align 4
+  %barr = call ptr @llvm.launder.invariant.group.p0(ptr %valptr)
+  %v2 = load i32, ptr %valptr
+  ret i32 %v2
+}
+
+define void @launder_and_ptr_arith() {
+; CHECK-LABEL: @launder_and_ptr_arith(
+; CHECK-NEXT:    ret void
+;
+  %valptr = alloca i32, align 4
+  %barr = call ptr @llvm.launder.invariant.group.p0(ptr %valptr)
+  %a2 = getelementptr inbounds i32, ptr %valptr, i32 0
+  ret void
+}
+
+define void @partial_use_of_alloca() {
+; CHECK-LABEL: @partial_use_of_alloca(
+; CHECK-NEXT:    [[VALPTR:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    store i32 0, ptr [[VALPTR]], align 4
+; CHECK-NEXT:    [[BARR:%.*]] = call ptr @llvm.launder.invariant.group.p0(ptr [[VALPTR]])
+; CHECK-NEXT:    [[LOAD_VAL:%.*]] = load i32, ptr [[VALPTR]], align 4
+; CHECK-NEXT:    [[COND:%.*]] = icmp eq i32 [[LOAD_VAL]], 0
+; CHECK-NEXT:    br i1 [[COND]], label [[USE_ALLOCA:%.*]], label [[END:%.*]]
+; CHECK:       use_alloca:
+; CHECK-NEXT:    call void @use(ptr nonnull [[VALPTR]])
+; CHECK-NEXT:    br label [[END]]
+; CHECK:       end:
+; CHECK-NEXT:    ret void
+;
+  %valptr = alloca i32, align 4
+  store i32 0, ptr %valptr, align 4
+  %barr = call ptr @llvm.launder.invariant.group.p0(ptr %valptr)
+  %load_val = load i32, ptr %valptr, align 4
+  %cond = icmp eq i32 %load_val, 0
+  br i1 %cond, label %use_alloca, label %end
+
+use_alloca:
+  call void @use(i32* nonnull %valptr)
+  br label %end
+
+end:
+  ret void
+}
+
+define void @partial_promotion_of_alloca() {
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nikic wrote:

Can you please also add some invariant group metadata to this test? It looks like the launder.invariant intrinsic gets dropped, which is okay only if the metadata also gets dropped.

https://github.com/llvm/llvm-project/pull/72056