From b1341191372a1208720ae23da8cca7749892da32 Mon Sep 17 00:00:00 2001 From: Dmitry Makogon Date: Tue, 6 Dec 2022 23:18:48 +0700 Subject: [PATCH] [SimplifyCFG] Prohibit hoisting of llvm.deoptimize calls This prohibits hoisiting identical llvm.deoptimize calls from 'then' and 'else' blocks of a conditional branch. This fixes a crash that happened because we didn't hoist the return instructions together with the llvm.deoptimize calls, so the verifier would crash. Differential Revision: https://reviews.llvm.org/D139437 --- llvm/lib/Transforms/Utils/SimplifyCFG.cpp | 6 ++++++ .../Transforms/SimplifyCFG/dont-hoist-deoptimize.ll | 19 ++++++++++++++++--- 2 files changed, 22 insertions(+), 3 deletions(-) diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index a1bc89e..fecf2b1 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -1471,6 +1471,12 @@ static bool isSafeToHoistInstr(Instruction *I, unsigned Flags) { if ((Flags & SkipImplicitControlFlow) && !isSafeToSpeculativelyExecute(I)) return false; + // Hoisting of llvm.deoptimize is only legal together with the next return + // instruction, which this pass is not always able to do. + if (auto *CB = dyn_cast(I)) + if (CB->getIntrinsicID() == Intrinsic::experimental_deoptimize) + return false; + // It's also unsafe/illegal to hoist an instruction above its instruction // operands BasicBlock *BB = I->getParent(); diff --git a/llvm/test/Transforms/SimplifyCFG/dont-hoist-deoptimize.ll b/llvm/test/Transforms/SimplifyCFG/dont-hoist-deoptimize.ll index 456e4cdb..6bfa967 100644 --- a/llvm/test/Transforms/SimplifyCFG/dont-hoist-deoptimize.ll +++ b/llvm/test/Transforms/SimplifyCFG/dont-hoist-deoptimize.ll @@ -1,13 +1,26 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; RUN: opt -S --passes='simplifycfg' -simplifycfg-hoist-common-skip-limit=0 %s | FileCheck %s target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128-ni:1-p2:32:8:8:32-ni:2" target triple = "x86_64-unknown-linux-gnu" declare void @llvm.experimental.deoptimize.isVoid(...) #0 -; REQUIRES: asserts -; XFAIL: * - define void @widget(i1 %arg) { +; CHECK-LABEL: @widget( +; CHECK-NEXT: bb: +; CHECK-NEXT: [[TMP:%.*]] = trunc i64 5 to i32 +; CHECK-NEXT: br i1 [[ARG:%.*]], label [[BB1:%.*]], label [[BB4:%.*]] +; CHECK: bb1: +; CHECK-NEXT: [[TMP2:%.*]] = trunc i64 0 to i32 +; CHECK-NEXT: [[TMP3:%.*]] = trunc i64 0 to i32 +; CHECK-NEXT: call void (...) @llvm.experimental.deoptimize.isVoid(i32 13) #[[ATTR0:[0-9]+]] [ "deopt"() ] +; CHECK-NEXT: ret void +; CHECK: bb4: +; CHECK-NEXT: [[TMP6:%.*]] = trunc i64 1 to i32 +; CHECK-NEXT: [[TMP7:%.*]] = trunc i64 0 to i32 +; CHECK-NEXT: call void (...) @llvm.experimental.deoptimize.isVoid(i32 13) #[[ATTR0]] [ "deopt"() ] +; CHECK-NEXT: ret void +; bb: br i1 %arg, label %bb1, label %bb4 -- 2.7.4