Skip to content

Commit

Permalink
Bail out jump threading on indirect branches only (llvm#117778)
Browse files Browse the repository at this point in the history 
Remove check for PHI in pred as pointed out in llvm#103688 
Reduced the testcase to remove redundant phi in pred

Fixes: llvm#102351
  • Loading branch information
@hiraditya
hiraditya authored Nov 26, 2024
1 parent 7ae61a3 commit 39601a6
Show file tree
Hide file tree
Showing 2 changed files with 60 additions and 84 deletions.
3 changes: 1 addition & 2 deletions llvm/lib/Transforms/Utils/Local.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1034,8 +1034,7 @@ CanRedirectPredsOfEmptyBBToSucc(BasicBlock *BB, BasicBlock *Succ,
return false;

if (any_of(BBPreds, [](const BasicBlock *Pred) {
return isa<PHINode>(Pred->begin()) &&
isa<IndirectBrInst>(Pred->getTerminator());
return isa<IndirectBrInst>(Pred->getTerminator());
}))
return false;

Expand Down
141 changes: 59 additions & 82 deletions llvm/test/Transforms/SimplifyCFG/switch-branch-fold-indirectbr-102351.ll
View file
Original file line number Diff line number Diff line change
@@ -1,104 +1,81 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --prefix-filecheck-ir-name pref --version 5
; RUN: opt < %s -passes=simplifycfg -S | FileCheck %s

target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

define dso_local noundef i32 @main() {
; CHECK-LABEL: define dso_local noundef i32 @main() {
define i32 @foo.1(i32 %arg, ptr %arg1) {
; CHECK-LABEL: define i32 @foo.1(
; CHECK-SAME: i32 [[ARG:%.*]], ptr [[ARG1:%.*]]) {
; CHECK-NEXT: [[BB:.*]]:
; CHECK-NEXT: [[ALLOCA:%.*]] = alloca [2 x ptr], align 16
; CHECK-NEXT: store ptr blockaddress(@main, %[[BB4:.*]]), ptr [[ALLOCA]], align 16, !tbaa [[TBAA0:![0-9]+]]
; CHECK-NEXT: store ptr blockaddress(@foo.1, %[[BB8:.*]]), ptr [[ALLOCA]], align 16
; CHECK-NEXT: [[GETELEMENTPTR:%.*]] = getelementptr inbounds [2 x ptr], ptr [[ALLOCA]], i64 0, i64 1
; CHECK-NEXT: store ptr blockaddress(@main, %[[BB10:.*]]), ptr [[GETELEMENTPTR]], align 8, !tbaa [[TBAA0]]
; CHECK-NEXT: br label %[[BB1:.*]]
; CHECK: [[BB1]]:
; CHECK-NEXT: [[PHI:%.*]] = phi i32 [ 0, %[[BB]] ], [ [[PHI8:%.*]], %[[BB7:.*]] ]
; CHECK-NEXT: [[PHI2:%.*]] = phi i32 [ 0, %[[BB]] ], [ [[PHI9:%.*]], %[[BB7]] ]
; CHECK-NEXT: switch i32 [[PHI]], label %[[BB7]] [
; CHECK-NEXT: i32 0, label %[[BB12:.*]]
; CHECK-NEXT: i32 1, label %[[BB4]]
; CHECK-NEXT: i32 2, label %[[BB6:.*]]
; CHECK-NEXT: store ptr blockaddress(@foo.1, %[[BB16:.*]]), ptr [[GETELEMENTPTR]], align 8
; CHECK-NEXT: br label %[[PREFBB2:.*]]
; CHECK: [[PREFBB2]]:
; CHECK-NEXT: [[PHI:%.*]] = phi i32 [ 0, %[[BB]] ], [ [[PHI14:%.*]], %[[BB13:.*]] ]
; CHECK-NEXT: [[PHI3:%.*]] = phi i32 [ 0, %[[BB]] ], [ [[PHI15:%.*]], %[[BB13]] ]
; CHECK-NEXT: switch i32 [[PHI]], label %[[BB13]] [
; CHECK-NEXT: i32 0, label %[[PREFBB18:.*]]
; CHECK-NEXT: i32 1, label %[[BB8]]
; CHECK-NEXT: i32 2, label %[[PREFBB11:.*]]
; CHECK-NEXT: ]
; CHECK: [[BB4]]:
; CHECK-NEXT: [[PHI5:%.*]] = phi i32 [ [[PHI13:%.*]], %[[BB12]] ], [ [[PHI2]], %[[BB1]] ]
; CHECK-NEXT: br label %[[BB7]]
; CHECK: [[BB6]]:
; CHECK-NEXT: [[CALL:%.*]] = call i32 @foo(i32 noundef [[PHI2]])
; CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[PHI2]], 1
; CHECK-NEXT: br label %[[BB12]]
; CHECK: [[BB7]]:
; CHECK-NEXT: [[PHI8]] = phi i32 [ [[PHI]], %[[BB1]] ], [ 2, %[[BB4]] ]
; CHECK-NEXT: [[PHI9]] = phi i32 [ [[PHI2]], %[[BB1]] ], [ [[PHI5]], %[[BB4]] ]
; CHECK-NEXT: br label %[[BB1]], !llvm.loop [[LOOP4:![0-9]+]]
; CHECK: [[BB10]]:
; CHECK-NEXT: [[CALL11:%.*]] = call i32 @foo(i32 noundef [[PHI13]])
; CHECK: [[BB8]]:
; CHECK-NEXT: [[PHI10:%.*]] = phi i32 [ [[ARG]], %[[PREFBB18]] ], [ [[PHI3]], %[[PREFBB2]] ]
; CHECK-NEXT: br label %[[BB13]]
; CHECK: [[PREFBB11]]:
; CHECK-NEXT: [[CALL:%.*]] = call i32 @wombat(i32 noundef [[PHI3]])
; CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[PHI3]], 1
; CHECK-NEXT: br label %[[PREFBB18]]
; CHECK: [[BB13]]:
; CHECK-NEXT: [[PHI14]] = phi i32 [ [[PHI]], %[[PREFBB2]] ], [ 2, %[[BB8]] ]
; CHECK-NEXT: [[PHI15]] = phi i32 [ [[PHI3]], %[[PREFBB2]] ], [ [[PHI10]], %[[BB8]] ]
; CHECK-NEXT: br label %[[PREFBB2]]
; CHECK: [[BB16]]:
; CHECK-NEXT: [[CALL17:%.*]] = call i32 @wombat(i32 noundef [[ARG]])
; CHECK-NEXT: ret i32 0
; CHECK: [[BB12]]:
; CHECK-NEXT: [[PHI13]] = phi i32 [ [[ADD]], %[[BB6]] ], [ [[PHI2]], %[[BB1]] ]
; CHECK-NEXT: [[SEXT:%.*]] = sext i32 [[PHI13]] to i64
; CHECK-NEXT: [[GETELEMENTPTR14:%.*]] = getelementptr inbounds [2 x ptr], ptr [[ALLOCA]], i64 0, i64 [[SEXT]]
; CHECK-NEXT: [[LOAD:%.*]] = load ptr, ptr [[GETELEMENTPTR14]], align 8, !tbaa [[TBAA0]]
; CHECK-NEXT: indirectbr ptr [[LOAD]], [label %[[BB4]], label %bb10]
; CHECK: [[PREFBB18]]:
; CHECK-NEXT: [[LOAD:%.*]] = load ptr, ptr [[ARG1]], align 8
; CHECK-NEXT: indirectbr ptr [[LOAD]], [label %[[BB8]], label %bb16]
;
bb:
%alloca = alloca [2 x ptr], align 16
store ptr blockaddress(@main, %bb4), ptr %alloca, align 16, !tbaa !0
store ptr blockaddress(@foo.1, %bb8), ptr %alloca, align 16
%getelementptr = getelementptr inbounds [2 x ptr], ptr %alloca, i64 0, i64 1
store ptr blockaddress(@main, %bb10), ptr %getelementptr, align 8, !tbaa !0
br label %bb1
store ptr blockaddress(@foo.1, %bb16), ptr %getelementptr, align 8
br label %bb2

bb1: ; preds = %bb7, %bb
%phi = phi i32 [ 0, %bb ], [ %phi8, %bb7 ]
%phi2 = phi i32 [ 0, %bb ], [ %phi9, %bb7 ]
switch i32 %phi, label %bb7 [
i32 0, label %bb3
i32 1, label %bb4
i32 2, label %bb6
bb2: ; preds = %bb13, %bb
%phi = phi i32 [ 0, %bb ], [ %phi14, %bb13 ]
%phi3 = phi i32 [ 0, %bb ], [ %phi15, %bb13 ]
switch i32 %phi, label %bb13 [
i32 0, label %bb5
i32 1, label %bb8
i32 2, label %bb11
]

bb3: ; preds = %bb1
br label %bb12
bb5: ; preds = %bb2
br label %bb18

bb4: ; preds = %bb12, %bb1
%phi5 = phi i32 [ %phi13, %bb12 ], [ %phi2, %bb1 ]
br label %bb7
bb8: ; preds = %bb18, %bb2
%phi10 = phi i32 [ %arg, %bb18 ], [ %phi3, %bb2 ]
br label %bb13

bb6: ; preds = %bb1
%call = call i32 @foo(i32 noundef %phi2)
%add = add nsw i32 %phi2, 1
br label %bb12
bb11: ; preds = %bb2
%call = call i32 @wombat(i32 noundef %phi3)
%add = add nsw i32 %phi3, 1
br label %bb18

bb7: ; preds = %bb4, %bb1
%phi8 = phi i32 [ %phi, %bb1 ], [ 2, %bb4 ]
%phi9 = phi i32 [ %phi2, %bb1 ], [ %phi5, %bb4 ]
br label %bb1, !llvm.loop !4
bb13: ; preds = %bb8, %bb2
%phi14 = phi i32 [ %phi, %bb2 ], [ 2, %bb8 ]
%phi15 = phi i32 [ %phi3, %bb2 ], [ %phi10, %bb8 ]
br label %bb2

bb10: ; preds = %bb12
%call11 = call i32 @foo(i32 noundef %phi13)
bb16: ; preds = %bb18
%call17 = call i32 @wombat(i32 noundef %arg)
ret i32 0

bb12: ; preds = %bb6, %bb3
%phi13 = phi i32 [ %add, %bb6 ], [ %phi2, %bb3 ]
%sext = sext i32 %phi13 to i64
%getelementptr14 = getelementptr inbounds [2 x ptr], ptr %alloca, i64 0, i64 %sext
%load = load ptr, ptr %getelementptr14, align 8, !tbaa !0
indirectbr ptr %load, [label %bb4, label %bb10]
bb18: ; preds = %bb11, %bb5
%load = load ptr, ptr %arg1, align 8
indirectbr ptr %load, [label %bb8, label %bb16]
}

declare i32 @foo(i32)

!0 = !{!1, !1, i64 0}
!1 = !{!"any pointer", !2, i64 0}
!2 = !{!"omnipotent char", !3, i64 0}
!3 = !{!"Simple C++ TBAA"}
!4 = !{!5, !5, i64 0}
!5 = !{!"int", !2, i64 0}
;.
; CHECK: [[TBAA0]] = !{[[META1:![0-9]+]], [[META1]], i64 0}
; CHECK: [[META1]] = !{!"any pointer", [[META2:![0-9]+]], i64 0}
; CHECK: [[META2]] = !{!"omnipotent char", [[META3:![0-9]+]], i64 0}
; CHECK: [[META3]] = !{!"Simple C++ TBAA"}
; CHECK: [[LOOP4]] = !{[[META5:![0-9]+]], [[META5]], i64 0}
; CHECK: [[META5]] = !{!"int", [[META2]], i64 0}
;.
declare i32 @wombat(i32)

0 comments on commit 39601a6

Please sign in to comment.