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llvm-mirror/test/Transforms/Sink/dead-user.ll
Changpeng Fang 7c619d4ea7 Sink: Handle instruction sink when a user is dead
Summary:
  The current instruction sink pass uses findNearestCommonDominator of all users to find block to sink the instruction to.
However, a user may be in a dead block, which will result in unexpected behavior.

This patch handles such cases by skipping dead blocks. This patch fixes:
https://bugs.llvm.org/show_bug.cgi?id=47415

Reviewers:
  MaskRay, arsenm

Differential Revision:
  https://reviews.llvm.org/D89166
2020-10-09 16:20:26 -07:00

43 lines
1.4 KiB
LLVM

; Compiler should not be broken with a dead user.
; RUN: opt -sink -S < %s | FileCheck %s
; CHECK-LABEL: @test(
; CHECK: bb.0:
; CHECK-NEXT: %conv = sext i16 %p1 to i32
; CHECK-NEXT: br i1 undef, label %bb.1, label %bb.3
; CHECK: bb.1: ; preds = %bb.0
; CHECK-NEXT: br label %bb.2
; CHECK: bb.2: ; preds = %bb.2, %bb.1
; CHECK-NEXT: %and.2 = and i32 undef, %conv
; CHECK-NEXT: br label %bb.2
; CHECK: bb.3: ; preds = %bb.3, %bb.0
; CHECK-NEXT: %and.3 = and i32 undef, %conv
; CHECK-NEXT: br label %bb.3
; CHECK: dead: ; preds = %dead
; CHECK-NEXT: %and.dead = and i32 undef, %conv
; CHECK-NEXT: br label %dead
define void @test(i16 %p1) {
bb.0:
%conv = sext i16 %p1 to i32
br i1 undef, label %bb.1, label %bb.3
bb.1: ; preds = %bb.0
br label %bb.2
bb.2: ; preds = %bb.2, %bb.1
%and.2 = and i32 undef, %conv
br label %bb.2
bb.3: ; preds = %bb.3, %bb.0
%and.3 = and i32 undef, %conv
br label %bb.3
dead: ; preds = %dead
%and.dead = and i32 undef, %conv
br label %dead
}