[llvm-branch-commits] [llvm] release/19.x: Bail out jump threading on indirect branches only (#117778) (PR #117869)
via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Wed Nov 27 02:59:47 PST 2024
https://github.com/llvmbot created https://github.com/llvm/llvm-project/pull/117869
Backport 3c9022c965b85951f30af140da591f819acef8a0 39601a6e5484de183bf525b7d0624e7890ccd8ab
Requested by: @nikic
>From 30e75e7bdac13b4139a687adbf42c289c31f3305 Mon Sep 17 00:00:00 2001
From: AdityaK <hiraditya at msn.com>
Date: Tue, 10 Sep 2024 22:39:02 -0700
Subject: [PATCH 1/2] Bail out jump threading on indirect branches (#103688)
The bug was introduced by
https://github.com/llvm/llvm-project/pull/68473
Fixes: #102351
(cherry picked from commit 3c9022c965b85951f30af140da591f819acef8a0)
---
llvm/lib/Transforms/Utils/Local.cpp | 11 +-
.../switch-branch-fold-indirectbr-102351.ll | 104 ++++++++++++++++++
2 files changed, 113 insertions(+), 2 deletions(-)
create mode 100644 llvm/test/Transforms/SimplifyCFG/switch-branch-fold-indirectbr-102351.ll
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 7192efe3f16b9d..4eb8dc1d2d6158 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -1028,7 +1028,14 @@ CanRedirectPredsOfEmptyBBToSucc(BasicBlock *BB, BasicBlock *Succ,
if (!BB->hasNPredecessorsOrMore(2))
return false;
- // Get single common predecessors of both BB and Succ
+ if (any_of(BBPreds, [](const BasicBlock *Pred) {
+ return isa<PHINode>(Pred->begin()) &&
+ isa<IndirectBrInst>(Pred->getTerminator());
+ }))
+ return false;
+
+ // Get the single common predecessor of both BB and Succ. Return false
+ // when there are more than one common predecessors.
for (BasicBlock *SuccPred : SuccPreds) {
if (BBPreds.count(SuccPred)) {
if (CommonPred)
@@ -1133,7 +1140,7 @@ bool llvm::TryToSimplifyUncondBranchFromEmptyBlock(BasicBlock *BB,
bool BBKillable = CanPropagatePredecessorsForPHIs(BB, Succ, BBPreds);
- // Even if we can not fold bB into Succ, we may be able to redirect the
+ // Even if we can not fold BB into Succ, we may be able to redirect the
// predecessors of BB to Succ.
bool BBPhisMergeable =
BBKillable ||
diff --git a/llvm/test/Transforms/SimplifyCFG/switch-branch-fold-indirectbr-102351.ll b/llvm/test/Transforms/SimplifyCFG/switch-branch-fold-indirectbr-102351.ll
new file mode 100644
index 00000000000000..03aee68fa4248c
--- /dev/null
+++ b/llvm/test/Transforms/SimplifyCFG/switch-branch-fold-indirectbr-102351.ll
@@ -0,0 +1,104 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --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() {
+; 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: [[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: ]
+; 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-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]
+;
+bb:
+ %alloca = alloca [2 x ptr], align 16
+ store ptr blockaddress(@main, %bb4), ptr %alloca, align 16, !tbaa !0
+ %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
+
+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
+ ]
+
+bb3: ; preds = %bb1
+ br label %bb12
+
+bb4: ; preds = %bb12, %bb1
+ %phi5 = phi i32 [ %phi13, %bb12 ], [ %phi2, %bb1 ]
+ br label %bb7
+
+bb6: ; preds = %bb1
+ %call = call i32 @foo(i32 noundef %phi2)
+ %add = add nsw i32 %phi2, 1
+ br label %bb12
+
+bb7: ; preds = %bb4, %bb1
+ %phi8 = phi i32 [ %phi, %bb1 ], [ 2, %bb4 ]
+ %phi9 = phi i32 [ %phi2, %bb1 ], [ %phi5, %bb4 ]
+ br label %bb1, !llvm.loop !4
+
+bb10: ; preds = %bb12
+ %call11 = call i32 @foo(i32 noundef %phi13)
+ 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]
+}
+
+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}
+;.
>From a87c6224086f35162c6001fbc87818b286d6af41 Mon Sep 17 00:00:00 2001
From: AdityaK <hiraditya at msn.com>
Date: Tue, 26 Nov 2024 14:57:28 -0800
Subject: [PATCH 2/2] Bail out jump threading on indirect branches only
(#117778)
Remove check for PHI in pred as pointed out in #103688
Reduced the testcase to remove redundant phi in pred
Fixes: #102351
(cherry picked from commit 39601a6e5484de183bf525b7d0624e7890ccd8ab)
---
llvm/lib/Transforms/Utils/Local.cpp | 3 +-
.../switch-branch-fold-indirectbr-102351.ll | 141 ++++++++----------
2 files changed, 60 insertions(+), 84 deletions(-)
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 4eb8dc1d2d6158..f68cbf62b9825f 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -1029,8 +1029,7 @@ 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;
diff --git a/llvm/test/Transforms/SimplifyCFG/switch-branch-fold-indirectbr-102351.ll b/llvm/test/Transforms/SimplifyCFG/switch-branch-fold-indirectbr-102351.ll
index 03aee68fa4248c..d3713be8358db4 100644
--- a/llvm/test/Transforms/SimplifyCFG/switch-branch-fold-indirectbr-102351.ll
+++ b/llvm/test/Transforms/SimplifyCFG/switch-branch-fold-indirectbr-102351.ll
@@ -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)
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