[llvm] Do not speculate select when it fails to simplify phi nodes. (PR #218159)
via llvm-commits
llvm-commits at lists.llvm.org
Sat Aug 22 13:01:59 PDT 2026
https://github.com/deadalnix created https://github.com/llvm/llvm-project/pull/218159
Generating select to remove phi node is worth it if we actually remove the phi node, but if not, then we avoid doing it.
Fixes #72152 .
>From 70d6aaad9e6eb5a81ae2527e65a1cd68a3366ff1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Amaury=20S=C3=A9chet?= <deadalnix at gmail.com>
Date: Sat, 22 Aug 2026 18:06:41 +0000
Subject: [PATCH] Do not speculate select when it fails to simplify phi nodes.
---
llvm/lib/Transforms/Utils/SimplifyCFG.cpp | 12 ++
.../PhaseOrdering/X86/vector-reductions.ll | 12 +-
.../Transforms/SimplifyCFG/PhiBlockMerge2.ll | 6 +-
llvm/test/Transforms/SimplifyCFG/PreferPhi.ll | 124 ++++++++++++++++++
.../SimplifyCFG/branch-fold-multiple.ll | 5 +-
.../Transforms/SimplifyCFG/branch-fold.ll | 5 +-
.../Transforms/SimplifyCFG/extract-cost.ll | 5 +-
.../Transforms/SimplifyCFG/multiple-phis.ll | 38 ++++--
.../SimplifyCFG/pr48778-sdiv-speculation.ll | 7 +-
.../Transforms/SimplifyCFG/return-merge.ll | 28 ++--
.../Transforms/SimplifyCFG/switch-on-const.ll | 9 +-
.../SimplifyCFG/switch-simplify-crash2.ll | 7 +-
12 files changed, 208 insertions(+), 50 deletions(-)
create mode 100644 llvm/test/Transforms/SimplifyCFG/PreferPhi.ll
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 2f9a4819f9984..6db188caa451e 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -3126,6 +3126,18 @@ static bool validateAndCostRequiredSelects(BasicBlock *BB, BasicBlock *ThenBB,
unsigned &SpeculatedInstructions,
InstructionCost &Cost,
const TargetTransformInfo &TTI) {
+ // If ThenBB is an empty BB, then the transformation's only goal
+ // is to simply phi nodes down the road. If the phi nodes cannot be
+ // simplified because they have other ancestors, then it is pointless
+ // to generate select instructions.
+ if (ThenBB->getFirstNonPHIOrDbgOrLifetime()->isTerminator()) {
+ for (BasicBlock *Pred : predecessors(EndBB)) {
+ if (Pred != BB && Pred != ThenBB) {
+ return false;
+ }
+ }
+ }
+
TargetTransformInfo::TargetCostKind CostKind =
BB->getParent()->hasMinSize()
? TargetTransformInfo::TCK_CodeSize
diff --git a/llvm/test/Transforms/PhaseOrdering/X86/vector-reductions.ll b/llvm/test/Transforms/PhaseOrdering/X86/vector-reductions.ll
index 78f68c420f6ab..e821789058050 100644
--- a/llvm/test/Transforms/PhaseOrdering/X86/vector-reductions.ll
+++ b/llvm/test/Transforms/PhaseOrdering/X86/vector-reductions.ll
@@ -277,13 +277,13 @@ define i1 @cmp_lt_gt(double %a, double %b, double %c) {
; CHECK-NEXT: [[TMP6:%.*]] = shufflevector <2 x double> [[TMP5]], <2 x double> poison, <2 x i32> zeroinitializer
; CHECK-NEXT: [[TMP7:%.*]] = fdiv <2 x double> [[TMP3]], [[TMP6]]
; CHECK-NEXT: [[TMP8:%.*]] = fcmp uge <2 x double> [[TMP7]], splat (double f0x3EB0C6F7A0B5ED8D)
-; CHECK-NEXT: [[SHIFT:%.*]] = shufflevector <2 x i1> [[TMP8]], <2 x i1> poison, <2 x i32> <i32 1, i32 poison>
-; CHECK-NEXT: [[FOLDEXTEXTBINOP:%.*]] = or <2 x i1> [[TMP8]], [[SHIFT]]
+; CHECK-NEXT: [[TMP10:%.*]] = bitcast <2 x i1> [[TMP8]] to i2
+; CHECK-NEXT: [[OR_COND:%.*]] = icmp eq i2 [[TMP10]], 0
; CHECK-NEXT: [[TMP9:%.*]] = fcmp ule <2 x double> [[TMP7]], splat (double 1.000000e+00)
-; CHECK-NEXT: [[SHIFT3:%.*]] = shufflevector <2 x i1> [[TMP9]], <2 x i1> poison, <2 x i32> <i32 1, i32 poison>
-; CHECK-NEXT: [[TMP10:%.*]] = or <2 x i1> [[TMP9]], [[SHIFT3]]
-; CHECK-NEXT: [[FOLDEXTEXTBINOP4:%.*]] = and <2 x i1> [[FOLDEXTEXTBINOP]], [[TMP10]]
-; CHECK-NEXT: [[RETVAL_0:%.*]] = extractelement <2 x i1> [[FOLDEXTEXTBINOP4]], i64 0
+; CHECK-NEXT: [[TMP11:%.*]] = bitcast <2 x i1> [[TMP9]] to i2
+; CHECK-NEXT: [[OR_COND1:%.*]] = icmp eq i2 [[TMP11]], 0
+; CHECK-NEXT: [[OR_COND5:%.*]] = or i1 [[OR_COND]], [[OR_COND1]]
+; CHECK-NEXT: [[RETVAL_0:%.*]] = select i1 [[OR_COND5]], i1 false, i1 true
; CHECK-NEXT: ret i1 [[RETVAL_0]]
;
entry:
diff --git a/llvm/test/Transforms/SimplifyCFG/PhiBlockMerge2.ll b/llvm/test/Transforms/SimplifyCFG/PhiBlockMerge2.ll
index f7daf31c2e212..e07661d071a06 100644
--- a/llvm/test/Transforms/SimplifyCFG/PhiBlockMerge2.ll
+++ b/llvm/test/Transforms/SimplifyCFG/PhiBlockMerge2.ll
@@ -14,10 +14,11 @@ define i32 @test(i1 %a, i1 %b) {
; 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 i1 [[D]], label [[M]], label [[Q:%.*]]
+; CHECK: Q:
; CHECK-NEXT: br label [[M]]
; CHECK: M:
-; CHECK-NEXT: [[W:%.*]] = phi i32 [ 0, [[TMP0:%.*]] ], [ [[SPEC_SELECT]], [[P]] ]
+; CHECK-NEXT: [[W:%.*]] = phi i32 [ 0, [[TMP0:%.*]] ], [ 1, [[Q]] ], [ 2, [[P]] ]
; CHECK-NEXT: [[R:%.*]] = add i32 [[W]], 1
; CHECK-NEXT: ret i32 [[R]]
;
@@ -37,4 +38,3 @@ M:
%R = add i32 %W, 1
ret i32 %R
}
-
diff --git a/llvm/test/Transforms/SimplifyCFG/PreferPhi.ll b/llvm/test/Transforms/SimplifyCFG/PreferPhi.ll
new file mode 100644
index 0000000000000..2f0d25a7abc05
--- /dev/null
+++ b/llvm/test/Transforms/SimplifyCFG/PreferPhi.ll
@@ -0,0 +1,124 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
+; RUN: opt -passes=simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S < %s | FileCheck %s
+
+declare i1 @cond()
+
+define ptr @a_or_null(ptr %a) {
+; CHECK-LABEL: define ptr @a_or_null(
+; CHECK-SAME: ptr [[A:%.*]]) {
+; CHECK-NEXT: [[ENTRY:.*]]:
+; CHECK-NEXT: [[C1:%.*]] = call i1 @cond()
+; CHECK-NEXT: br i1 [[C1]], label %[[COMMON_RET:.*]], label %[[CONTINUE:.*]]
+; CHECK: [[CONTINUE]]:
+; CHECK-NEXT: [[C2:%.*]] = call i1 @cond()
+; CHECK-NEXT: br i1 [[C2]], label %[[SUCCESS:.*]], label %[[COMMON_RET]]
+; CHECK: [[COMMON_RET]]:
+; CHECK-NEXT: [[COMMON_RET_OP:%.*]] = phi ptr [ [[A]], %[[SUCCESS]] ], [ null, %[[CONTINUE]] ], [ null, %[[ENTRY]] ]
+; CHECK-NEXT: ret ptr [[COMMON_RET_OP]]
+; CHECK: [[SUCCESS]]:
+; CHECK-NEXT: br label %[[COMMON_RET]]
+;
+entry:
+ %c1 = call i1 @cond()
+ br i1 %c1, label %fail, label %continue
+
+continue:
+ %c2 = call i1 @cond()
+ br i1 %c2, label %success, label %fail
+
+fail:
+ ret ptr null
+
+success:
+ ret ptr %a
+}
+
+define ptr @a_or_null_select(ptr %a) {
+; CHECK-LABEL: define ptr @a_or_null_select(
+; CHECK-SAME: ptr [[A:%.*]]) {
+; CHECK-NEXT: [[ENTRY:.*]]:
+; CHECK-NEXT: [[C1:%.*]] = call i1 @cond()
+; CHECK-NEXT: br i1 [[C1]], label %[[EXIT:.*]], label %[[CONTINUE:.*]]
+; CHECK: [[CONTINUE]]:
+; CHECK-NEXT: [[C2:%.*]] = call i1 @cond()
+; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[C2]], ptr [[A]], ptr null
+; CHECK-NEXT: br label %[[EXIT]]
+; CHECK: [[EXIT]]:
+; CHECK-NEXT: [[RET:%.*]] = phi ptr [ null, %[[ENTRY]] ], [ [[SELECT]], %[[CONTINUE]] ]
+; CHECK-NEXT: ret ptr [[RET]]
+;
+entry:
+ %c1 = call i1 @cond()
+ br i1 %c1, label %exit, label %continue
+
+continue:
+ %c2 = call i1 @cond()
+ %select = select i1 %c2, ptr %a, ptr null
+ br label %exit
+
+exit:
+ %ret = phi ptr [ null, %entry ], [ %select, %continue ]
+ ret ptr %ret
+}
+
+define ptr @a_or_null_phi1(ptr %a) {
+; CHECK-LABEL: define ptr @a_or_null_phi1(
+; CHECK-SAME: ptr [[A:%.*]]) {
+; CHECK-NEXT: [[ENTRY:.*:]]
+; CHECK-NEXT: [[C1:%.*]] = call i1 @cond()
+; CHECK-NEXT: br i1 [[C1]], label %[[FAIL:.*]], label %[[CONTINUE:.*]]
+; CHECK: [[CONTINUE]]:
+; CHECK-NEXT: [[C2:%.*]] = call i1 @cond()
+; CHECK-NEXT: br i1 [[C2]], label %[[EXIT:.*]], label %[[FAIL]]
+; CHECK: [[FAIL]]:
+; CHECK-NEXT: br label %[[EXIT]]
+; CHECK: [[EXIT]]:
+; CHECK-NEXT: [[RET:%.*]] = phi ptr [ null, %[[FAIL]] ], [ [[A]], %[[CONTINUE]] ]
+; CHECK-NEXT: ret ptr [[RET]]
+;
+entry:
+ %c1 = call i1 @cond()
+ br i1 %c1, label %fail, label %continue
+
+continue:
+ %c2 = call i1 @cond()
+ br i1 %c2, label %exit, label %fail
+
+fail:
+ br label %exit
+
+exit:
+ %ret = phi ptr [ null, %fail ], [ %a, %continue ]
+ ret ptr %ret
+}
+
+define ptr @a_or_null_phi2(ptr %a) {
+; CHECK-LABEL: define ptr @a_or_null_phi2(
+; CHECK-SAME: ptr [[A:%.*]]) {
+; CHECK-NEXT: [[ENTRY:.*:]]
+; CHECK-NEXT: [[C1:%.*]] = call i1 @cond()
+; CHECK-NEXT: br i1 [[C1]], label %[[FAIL:.*]], label %[[CONTINUE:.*]]
+; CHECK: [[CONTINUE]]:
+; CHECK-NEXT: [[C2:%.*]] = call i1 @cond()
+; CHECK-NEXT: br i1 [[C2]], label %[[EXIT:.*]], label %[[FAIL]]
+; CHECK: [[FAIL]]:
+; CHECK-NEXT: br label %[[EXIT]]
+; CHECK: [[EXIT]]:
+; CHECK-NEXT: [[RET:%.*]] = phi ptr [ null, %[[FAIL]] ], [ [[A]], %[[CONTINUE]] ]
+; CHECK-NEXT: ret ptr [[RET]]
+;
+entry:
+ %c1 = call i1 @cond()
+ br i1 %c1, label %fail, label %continue
+
+continue:
+ %c2 = call i1 @cond()
+ br i1 %c2, label %exit, label %fail
+
+fail:
+ br label %exit
+
+exit:
+ %ret = phi ptr [ null, %fail ], [ %a, %continue ]
+ ret ptr %ret
+}
diff --git a/llvm/test/Transforms/SimplifyCFG/branch-fold-multiple.ll b/llvm/test/Transforms/SimplifyCFG/branch-fold-multiple.ll
index fd400632a5916..7077b224abba7 100644
--- a/llvm/test/Transforms/SimplifyCFG/branch-fold-multiple.ll
+++ b/llvm/test/Transforms/SimplifyCFG/branch-fold-multiple.ll
@@ -114,10 +114,11 @@ define i1 @test3(i32 %0, i32 %1, i32 %2, i32 %3) {
; CHECK-NEXT: [[OR_COND:%.*]] = select i1 [[CMP2_1]], i1 true, i1 [[CMP2_2]]
; CHECK-NEXT: [[CMP2_3:%.*]] = icmp sgt i32 [[TMP3]], 0
; CHECK-NEXT: [[OR_COND1:%.*]] = select i1 [[OR_COND]], i1 true, i1 [[CMP2_3]]
-; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[OR_COND1]], i1 false, i1 true
+; CHECK-NEXT: br i1 [[OR_COND1]], label [[CLEANUP]], label [[FOR_COND3:%.*]]
+; CHECK: for.cond.3:
; CHECK-NEXT: br label [[CLEANUP]]
; CHECK: cleanup:
-; CHECK-NEXT: [[CMP:%.*]] = phi i1 [ false, [[ENTRY:%.*]] ], [ [[SPEC_SELECT]], [[FOR_COND]] ]
+; CHECK-NEXT: [[CMP:%.*]] = phi i1 [ false, [[ENTRY:%.*]] ], [ false, [[FOR_COND]] ], [ true, [[FOR_COND3]] ]
; CHECK-NEXT: ret i1 [[CMP]]
;
entry:
diff --git a/llvm/test/Transforms/SimplifyCFG/branch-fold.ll b/llvm/test/Transforms/SimplifyCFG/branch-fold.ll
index 58f5b9291673e..ce50acc3fca90 100644
--- a/llvm/test/Transforms/SimplifyCFG/branch-fold.ll
+++ b/llvm/test/Transforms/SimplifyCFG/branch-fold.ll
@@ -122,10 +122,11 @@ define i8 @common_pred(i8 noundef %arg, i1 %c1, i1 %c2) {
; CHECK-NEXT: br i1 [[C1:%.*]], label [[COMMONPRED:%.*]], label [[SUCC:%.*]]
; CHECK: CommonPred:
; CHECK-NEXT: call void @dummy()
-; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[C2:%.*]], i8 4, i8 1
+; CHECK-NEXT: br i1 [[C2:%.*]], label [[SUCC]], label [[BB:%.*]]
+; CHECK: BB:
; CHECK-NEXT: br label [[SUCC]]
; CHECK: Succ:
-; CHECK-NEXT: [[PHI2:%.*]] = phi i8 [ [[SPEC_SELECT]], [[COMMONPRED]] ], [ 0, [[PRED:%.*]] ]
+; CHECK-NEXT: [[PHI2:%.*]] = phi i8 [ 4, [[COMMONPRED]] ], [ 0, [[PRED:%.*]] ], [ 1, [[BB]] ]
; CHECK-NEXT: ret i8 [[PHI2]]
;
Pred:
diff --git a/llvm/test/Transforms/SimplifyCFG/extract-cost.ll b/llvm/test/Transforms/SimplifyCFG/extract-cost.ll
index 4290d9069e5bb..f1bd7f18c996c 100644
--- a/llvm/test/Transforms/SimplifyCFG/extract-cost.ll
+++ b/llvm/test/Transforms/SimplifyCFG/extract-cost.ll
@@ -37,8 +37,9 @@ define i1 @PR32078(<4 x i32> %a, <4 x i32> %b) {
; CHECK-NEXT: [[CMP0_NOT:%.*]] = xor i1 [[CMP0]], true
; CHECK-NEXT: [[CMP1_NOT:%.*]] = xor i1 [[CMP1]], true
; CHECK-NEXT: [[BRMERGE:%.*]] = select i1 [[CMP0_NOT]], i1 true, i1 [[CMP1_NOT]]
-; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[CMP2]], i1 [[CMP3]], i1 false
-; CHECK-NEXT: [[R:%.*]] = select i1 [[BRMERGE]], i1 false, i1 [[SPEC_SELECT]]
+; CHECK-NEXT: [[CMP2_NOT:%.*]] = xor i1 [[CMP2]], true
+; CHECK-NEXT: [[BRMERGE1:%.*]] = select i1 [[BRMERGE]], i1 true, i1 [[CMP2_NOT]]
+; CHECK-NEXT: [[R:%.*]] = select i1 [[BRMERGE1]], i1 false, i1 [[CMP3]]
; CHECK-NEXT: ret i1 [[R]]
;
entry:
diff --git a/llvm/test/Transforms/SimplifyCFG/multiple-phis.ll b/llvm/test/Transforms/SimplifyCFG/multiple-phis.ll
index 7b188ba787664..eb11bc8578b00 100644
--- a/llvm/test/Transforms/SimplifyCFG/multiple-phis.ll
+++ b/llvm/test/Transforms/SimplifyCFG/multiple-phis.ll
@@ -63,10 +63,16 @@ while.end: ; preds = %while.cond
define i32 @merge0(i1 %c1, i1 %c2, i1 %c3) {
; CHECK-LABEL: define i32 @merge0
; CHECK-SAME: (i1 [[C1:%.*]], i1 [[C2:%.*]], i1 [[C3:%.*]]) {
-; CHECK-NEXT: j2:
-; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[C3]], i32 2, i32 3
+; CHECK-NEXT: br i1 [[C1]], label [[IF1:%.*]], label [[ELSE1:%.*]]
+; CHECK: if1:
; CHECK-NEXT: [[DOT:%.*]] = select i1 [[C2]], i32 0, i32 1
-; CHECK-NEXT: [[PHI2:%.*]] = select i1 [[C1]], i32 [[DOT]], i32 [[SPEC_SELECT]]
+; CHECK-NEXT: br label [[J2:%.*]]
+; CHECK: else1:
+; CHECK-NEXT: br i1 [[C3]], label [[J1:%.*]], label [[J2]]
+; CHECK: j1:
+; CHECK-NEXT: br label [[J2]]
+; CHECK: j2:
+; CHECK-NEXT: [[PHI2:%.*]] = phi i32 [ 3, [[ELSE1]] ], [ [[DOT]], [[IF1]] ], [ 2, [[J1]] ]
; CHECK-NEXT: ret i32 [[PHI2]]
;
br i1 %c1, label %if1, label %else1
@@ -106,12 +112,13 @@ define i8 @merge1(i8 noundef %arg, i1 %c1, i1 %c2) {
; CHECK-NEXT: [[C2_NOT:%.*]] = xor i1 [[C2]], true
; CHECK-NEXT: [[BRMERGE:%.*]] = select i1 [[C1_NOT]], i1 true, i1 [[C2_NOT]]
; CHECK-NEXT: [[DOTMUX:%.*]] = select i1 [[C1_NOT]], i8 0, i8 3
-; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[BRMERGE]], i8 [[DOTMUX]], i8 4
-; CHECK-NEXT: br label [[SUCC]]
+; CHECK-NEXT: br i1 [[BRMERGE]], label [[BB:%.*]], label [[SUCC]]
; CHECK: case2:
; CHECK-NEXT: br label [[SUCC]]
+; CHECK: BB:
+; CHECK-NEXT: br label [[SUCC]]
; CHECK: Succ:
-; CHECK-NEXT: [[PHI2:%.*]] = phi i8 [ [[SPEC_SELECT]], [[CASE0]] ], [ 1, [[ENTRY:%.*]] ], [ 2, [[CASE2]] ]
+; CHECK-NEXT: [[PHI2:%.*]] = phi i8 [ 4, [[CASE0]] ], [ 1, [[ENTRY:%.*]] ], [ 2, [[CASE2]] ], [ [[DOTMUX]], [[BB]] ]
; CHECK-NEXT: ret i8 [[PHI2]]
;
entry:
@@ -162,12 +169,13 @@ define i8 @merge1_unfoldable_one_block(i8 noundef %arg, i1 %c1, i1 %c2) {
; CHECK-NEXT: [[C2_NOT:%.*]] = xor i1 [[C2]], true
; CHECK-NEXT: [[BRMERGE:%.*]] = select i1 [[C1_NOT]], i1 true, i1 [[C2_NOT]]
; CHECK-NEXT: [[DOTMUX:%.*]] = select i1 [[C1_NOT]], i8 0, i8 3
-; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[BRMERGE]], i8 [[DOTMUX]], i8 4
-; CHECK-NEXT: br label [[SUCC]]
+; CHECK-NEXT: br i1 [[BRMERGE]], label [[BB:%.*]], label [[SUCC]]
; CHECK: case2:
; CHECK-NEXT: br label [[SUCC]]
+; CHECK: BB:
+; CHECK-NEXT: br label [[SUCC]]
; CHECK: Succ:
-; CHECK-NEXT: [[PHI2:%.*]] = phi i8 [ [[SPEC_SELECT]], [[CASE0]] ], [ 1, [[ENTRY:%.*]] ], [ 2, [[CASE2]] ]
+; CHECK-NEXT: [[PHI2:%.*]] = phi i8 [ 4, [[CASE0]] ], [ 1, [[ENTRY:%.*]] ], [ 2, [[CASE2]] ], [ [[DOTMUX]], [[BB]] ]
; CHECK-NEXT: ret i8 [[PHI2]]
;
entry:
@@ -219,13 +227,14 @@ define i8 @merge1_unfoldable_two_block(i8 noundef %arg, i1 %c1, i1 %c2) {
; CHECK-NEXT: [[C2_NOT:%.*]] = xor i1 [[C2]], true
; CHECK-NEXT: [[BRMERGE:%.*]] = select i1 [[C1_NOT]], i1 true, i1 [[C2_NOT]]
; CHECK-NEXT: [[DOTMUX:%.*]] = select i1 [[C1_NOT]], i8 0, i8 3
-; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[BRMERGE]], i8 [[DOTMUX]], i8 4
-; CHECK-NEXT: br label [[SUCC]]
+; CHECK-NEXT: br i1 [[BRMERGE]], label [[BB:%.*]], label [[SUCC]]
; CHECK: case1:
; CHECK-NEXT: call void @dummy()
; CHECK-NEXT: br label [[SUCC]]
+; CHECK: BB:
+; CHECK-NEXT: br label [[SUCC]]
; CHECK: Succ:
-; CHECK-NEXT: [[PHI2:%.*]] = phi i8 [ [[SPEC_SELECT]], [[CASE0]] ], [ 1, [[CASE1]] ], [ 2, [[ENTRY:%.*]] ]
+; CHECK-NEXT: [[PHI2:%.*]] = phi i8 [ 4, [[CASE0]] ], [ 1, [[CASE1]] ], [ 2, [[ENTRY:%.*]] ], [ [[DOTMUX]], [[BB]] ]
; CHECK-NEXT: ret i8 [[PHI2]]
;
entry:
@@ -283,10 +292,11 @@ define i8 @merge1_unfoldable_all_block(i8 noundef %arg, i1 %c1, i1 %c2) {
; CHECK-NEXT: br label [[SUCC]]
; CHECK: CommonPred:
; CHECK-NEXT: call void @dummy()
-; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[C2]], i8 4, i8 3
+; CHECK-NEXT: br i1 [[C2]], label [[SUCC]], label [[BB:%.*]]
+; CHECK: BB:
; CHECK-NEXT: br label [[SUCC]]
; CHECK: Succ:
-; CHECK-NEXT: [[PHI2:%.*]] = phi i8 [ [[SPEC_SELECT]], [[COMMONPRED]] ], [ 0, [[CASE0]] ], [ 1, [[CASE1]] ], [ 2, [[CASE2]] ]
+; CHECK-NEXT: [[PHI2:%.*]] = phi i8 [ 4, [[COMMONPRED]] ], [ 0, [[CASE0]] ], [ 1, [[CASE1]] ], [ 2, [[CASE2]] ], [ 3, [[BB]] ]
; CHECK-NEXT: ret i8 [[PHI2]]
;
entry:
diff --git a/llvm/test/Transforms/SimplifyCFG/pr48778-sdiv-speculation.ll b/llvm/test/Transforms/SimplifyCFG/pr48778-sdiv-speculation.ll
index fe38dd80246e1..7fc0623091009 100644
--- a/llvm/test/Transforms/SimplifyCFG/pr48778-sdiv-speculation.ll
+++ b/llvm/test/Transforms/SimplifyCFG/pr48778-sdiv-speculation.ll
@@ -8,11 +8,12 @@ define i32 @test(i1 %cmp) {
; CHECK: if:
; CHECK-NEXT: [[DIV:%.*]] = sdiv i32 -2147483648, -1
; CHECK-NEXT: [[CMP2:%.*]] = icmp ne i32 [[DIV]], 0
-; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[CMP2]], i32 1, i32 0
-; CHECK-NEXT: br label [[COMMON_RET]]
+; CHECK-NEXT: br i1 [[CMP2]], label [[END:%.*]], label [[COMMON_RET]]
; CHECK: common.ret:
-; CHECK-NEXT: [[COMMON_RET_OP:%.*]] = phi i32 [ 0, [[TMP0:%.*]] ], [ [[SPEC_SELECT]], [[IF]] ]
+; CHECK-NEXT: [[COMMON_RET_OP:%.*]] = phi i32 [ 1, [[END]] ], [ 0, [[IF]] ], [ 0, [[TMP0:%.*]] ]
; CHECK-NEXT: ret i32 [[COMMON_RET_OP]]
+; CHECK: end:
+; CHECK-NEXT: br label [[COMMON_RET]]
;
br i1 %cmp, label %if, label %else
diff --git a/llvm/test/Transforms/SimplifyCFG/return-merge.ll b/llvm/test/Transforms/SimplifyCFG/return-merge.ll
index 2269b62ef5909..f7ddf45886946 100644
--- a/llvm/test/Transforms/SimplifyCFG/return-merge.ll
+++ b/llvm/test/Transforms/SimplifyCFG/return-merge.ll
@@ -12,8 +12,8 @@ define i32 @test1(i1 %C) {
; DBGINFO-LABEL: @test1(
; DBGINFO-NEXT: entry:
; DBGINFO-NEXT: #dbg_value(i32 0, [[META9:![0-9]+]], !DIExpression(), [[META11:![0-9]+]])
-; DBGINFO-NEXT: [[DOT:%.*]] = select i1 [[C:%.*]], i32 1, i32 0
-; DBGINFO-NEXT: ret i32 [[DOT]], !dbg [[DBG12:![0-9]+]]
+; DBGINFO-NEXT: [[DOT:%.*]] = select i1 [[C:%.*]], i32 1, i32 0, !dbg [[DBG12:![0-9]+]]
+; DBGINFO-NEXT: ret i32 [[DOT]], !dbg [[DBG12]]
;
entry:
br i1 %C, label %T, label %F
@@ -49,13 +49,14 @@ define i32 @test3(i1 %C0, i1 %C1, i32 %v0, i32 %v1, i32 %v2) {
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @sideeffect0()
; CHECK-NEXT: br i1 [[C0:%.*]], label [[T:%.*]], label [[F:%.*]]
+; CHECK: T.cont:
+; CHECK-NEXT: br label [[END:%.*]]
; CHECK: end:
-; CHECK-NEXT: [[R:%.*]] = phi i32 [ [[V2:%.*]], [[F]] ], [ [[SPEC_SELECT:%.*]], [[T]] ]
+; CHECK-NEXT: [[R:%.*]] = phi i32 [ [[V0:%.*]], [[TCONT:%.*]] ], [ [[V1:%.*]], [[T]] ], [ [[V2:%.*]], [[F]] ]
; CHECK-NEXT: ret i32 [[R]]
; CHECK: T:
; CHECK-NEXT: call void @sideeffect1()
-; CHECK-NEXT: [[SPEC_SELECT]] = select i1 [[C1:%.*]], i32 [[V0:%.*]], i32 [[V1:%.*]]
-; CHECK-NEXT: br label [[END:%.*]]
+; CHECK-NEXT: br i1 [[C1:%.*]], label [[TCONT]], label [[END]]
; CHECK: F:
; CHECK-NEXT: call void @sideeffect2()
; CHECK-NEXT: br label [[END]]
@@ -64,17 +65,18 @@ define i32 @test3(i1 %C0, i1 %C1, i32 %v0, i32 %v1, i32 %v2) {
; DBGINFO-NEXT: entry:
; DBGINFO-NEXT: call void @sideeffect0(), !dbg [[DBG21:![0-9]+]]
; DBGINFO-NEXT: br i1 [[C0:%.*]], label [[T:%.*]], label [[F:%.*]], !dbg [[DBG22:![0-9]+]]
+; DBGINFO: T.cont:
+; DBGINFO-NEXT: br label [[END:%.*]], !dbg [[DBG23:![0-9]+]]
; DBGINFO: end:
-; DBGINFO-NEXT: [[R:%.*]] = phi i32 [ [[V2:%.*]], [[F]] ], [ [[SPEC_SELECT:%.*]], [[T]] ], !dbg [[DBG23:![0-9]+]]
-; DBGINFO-NEXT: #dbg_value(i32 [[R]], [[META20:![0-9]+]], !DIExpression(), [[DBG23]])
-; DBGINFO-NEXT: ret i32 [[R]], !dbg [[DBG24:![0-9]+]]
+; DBGINFO-NEXT: [[R:%.*]] = phi i32 [ [[V0:%.*]], [[T_CONT:%.*]] ], [ [[V1:%.*]], [[T]] ], [ [[V2:%.*]], [[F]] ], !dbg [[DBG24:![0-9]+]]
+; DBGINFO-NEXT: #dbg_value(i32 [[R]], [[META20:![0-9]+]], !DIExpression(), [[DBG24]])
+; DBGINFO-NEXT: ret i32 [[R]], !dbg [[DBG25:![0-9]+]]
; DBGINFO: T:
-; DBGINFO-NEXT: call void @sideeffect1(), !dbg [[DBG25:![0-9]+]]
-; DBGINFO-NEXT: [[SPEC_SELECT]] = select i1 [[C1:%.*]], i32 [[V0:%.*]], i32 [[V1:%.*]], !dbg [[DBG26:![0-9]+]]
-; DBGINFO-NEXT: br label [[END:%.*]], !dbg [[DBG26]]
+; DBGINFO-NEXT: call void @sideeffect1(), !dbg [[DBG26:![0-9]+]]
+; DBGINFO-NEXT: br i1 [[C1:%.*]], label [[T_CONT]], label [[END]], !dbg [[DBG27:![0-9]+]]
; DBGINFO: F:
-; DBGINFO-NEXT: call void @sideeffect2(), !dbg [[DBG27:![0-9]+]]
-; DBGINFO-NEXT: br label [[END]], !dbg [[DBG28:![0-9]+]]
+; DBGINFO-NEXT: call void @sideeffect2(), !dbg [[DBG28:![0-9]+]]
+; DBGINFO-NEXT: br label [[END]], !dbg [[DBG29:![0-9]+]]
;
entry:
call void @sideeffect0()
diff --git a/llvm/test/Transforms/SimplifyCFG/switch-on-const.ll b/llvm/test/Transforms/SimplifyCFG/switch-on-const.ll
index 6e33a381fb463..254a0f1386d0f 100644
--- a/llvm/test/Transforms/SimplifyCFG/switch-on-const.ll
+++ b/llvm/test/Transforms/SimplifyCFG/switch-on-const.ll
@@ -128,10 +128,15 @@ define i32 @xyzzy(i64 %x, i64 %y) {
; CHECK-LABEL: @xyzzy(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[EQ:%.*]] = icmp eq i64 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: br i1 [[EQ]], label [[COMMON_RET:%.*]], label [[CONT:%.*]]
+; CHECK: cont:
; CHECK-NEXT: [[LT:%.*]] = icmp slt i64 [[X]], [[Y]]
-; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[LT]], i32 -1, i32 1
-; CHECK-NEXT: [[COMMON_RET_OP:%.*]] = select i1 [[EQ]], i32 0, i32 [[SPEC_SELECT]]
+; CHECK-NEXT: br i1 [[LT]], label [[A:%.*]], label [[COMMON_RET]]
+; CHECK: common.ret:
+; CHECK-NEXT: [[COMMON_RET_OP:%.*]] = phi i32 [ -1, [[A]] ], [ 0, [[ENTRY:%.*]] ], [ 1, [[CONT]] ]
; CHECK-NEXT: ret i32 [[COMMON_RET_OP]]
+; CHECK: a:
+; CHECK-NEXT: br label [[COMMON_RET]]
;
entry:
%eq = icmp eq i64 %x, %y
diff --git a/llvm/test/Transforms/SimplifyCFG/switch-simplify-crash2.ll b/llvm/test/Transforms/SimplifyCFG/switch-simplify-crash2.ll
index 526dae9d0396b..6a10fc32424b3 100644
--- a/llvm/test/Transforms/SimplifyCFG/switch-simplify-crash2.ll
+++ b/llvm/test/Transforms/SimplifyCFG/switch-simplify-crash2.ll
@@ -5,11 +5,12 @@ define i8 @test() {
; CHECK-LABEL: @test(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[LOOP2:%.*]]
+; CHECK: loop:
+; CHECK-NEXT: br label [[LOOP2]]
; CHECK: loop2:
-; CHECK-NEXT: [[PHI2:%.*]] = phi i8 [ [[SPEC_SELECT:%.*]], [[LOOP2]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT: [[PHI2:%.*]] = phi i8 [ 0, [[LOOP2]] ], [ 0, [[ENTRY:%.*]] ], [ [[PHI2]], [[LOOP:%.*]] ]
; CHECK-NEXT: [[COND:%.*]] = icmp eq i8 [[PHI2]], 0
-; CHECK-NEXT: [[SPEC_SELECT]] = select i1 [[COND]], i8 0, i8 [[PHI2]]
-; CHECK-NEXT: br label [[LOOP2]]
+; CHECK-NEXT: br i1 [[COND]], label [[LOOP2]], label [[LOOP]]
;
entry:
br label %loop
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