llvm-project/llvm/test/Transforms/SimplifyCFG/PhiBlockMerge2.ll

41 lines
1.1 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; Test merging of blocks that only have PHI nodes in them. This tests the case
; where the mergedinto block doesn't have any PHI nodes, and is in fact
; dominated by the block-to-be-eliminated
;
; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
;
declare i1 @foo()
define i32 @test(i1 %a, i1 %b) {
; CHECK-LABEL: @test(
; CHECK-NEXT: [[C:%.*]] = call i1 @foo()
; CHECK-NEXT: br i1 [[C]], label [[M:%.*]], label [[P:%.*]]
; CHECK: P:
; CHECK-NEXT: [[D:%.*]] = call i1 @foo()
; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[D]], i32 2, i32 1
; CHECK-NEXT: br label [[M]]
; CHECK: M:
; CHECK-NEXT: [[W:%.*]] = phi i32 [ 0, [[TMP0:%.*]] ], [ [[SPEC_SELECT]], [[P]] ]
; CHECK-NEXT: [[R:%.*]] = add i32 [[W]], 1
; CHECK-NEXT: ret i32 [[R]]
;
%c = call i1 @foo()
br i1 %c, label %N, label %P
P:
%d = call i1 @foo()
br i1 %d, label %N, label %Q
Q:
br label %N
N:
%W = phi i32 [0, %0], [1, %Q], [2, %P]
; This block should be foldable into M
br label %M
M:
%R = add i32 %W, 1
ret i32 %R
}