[PATCH] D139437: [SimplifyCFG] Prohibit hoisting of llvm.deoptimize calls

[Dmitry Makogon via Phabricator via llvm-commits]

dmakogon updated this revision to Diff 480785.
dmakogon retitled this revision from "[SimplifyCFG] Prohibit hoisting from deoptimize blocks" to "[SimplifyCFG] Prohibit hoisting of llvm.deoptimize calls".
dmakogon edited the summary of this revision.
dmakogon added a comment.

Instead of prohibiting hoisting from deoptimize blocks, just disallow hoisiting of llvm.deoptimize calls


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D139437/new/

https://reviews.llvm.org/D139437

Files:
  llvm/lib/Transforms/Utils/SimplifyCFG.cpp
  llvm/test/Transforms/SimplifyCFG/dont-hoist-deoptimize.ll


Index: llvm/test/Transforms/SimplifyCFG/dont-hoist-deoptimize.ll
===================================================================
--- llvm/test/Transforms/SimplifyCFG/dont-hoist-deoptimize.ll
+++ 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<hoist-common-insts>' -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"(i32 0, i32 1, i32 0, i32 502, i32 4, i32 35, i32 0, i32 0, ptr addrspace(1) null, i32 3, i32 -99, i32 0, ptr addrspace(1) null, i32 3, i32 -99, i32 0, ptr addrspace(1) null, i32 7, ptr null, i32 3, i32 0, i32 3, i32 0, i32 3, i32 [[TMP3]], i32 3, i32 0, i32 3, i32 0, i32 3, i32 [[TMP]], i32 3, i32 0, i32 3, i32 -99, i32 3, i32 0, i32 3, i32 14, i32 3, i32 0, i32 3, i32 -99, i32 3, i32 0, i32 3, i32 0, i32 3, i32 0, i32 3, i32 0, i32 0, ptr addrspace(1) null, i32 3, float 0.000000e+00, i32 4, double 0.000000e+00, i32 7, ptr null, i32 0, ptr addrspace(1) null, i32 0, ptr addrspace(1) null, i32 0, ptr addrspace(1) null, i32 7, ptr null, i32 7, ptr null, i32 0, ptr addrspace(1) null, i32 0, ptr addrspace(1) null, i32 0, ptr addrspace(1) null, i32 0, ptr addrspace(1) null, i32 7, ptr null, i32 7, ptr null, i32 7, ptr null, i32 7, ptr null) ]
+; 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"(i32 0, i32 1, i32 0, i32 502, i32 4, i32 35, i32 0, i32 0, ptr addrspace(1) null, i32 3, i32 -99, i32 0, ptr addrspace(1) null, i32 3, i32 -99, i32 0, ptr addrspace(1) null, i32 7, ptr null, i32 3, i32 0, i32 3, i32 0, i32 3, i32 [[TMP7]], i32 3, i32 0, i32 3, i32 0, i32 3, i32 [[TMP]], i32 3, i32 0, i32 3, i32 -99, i32 3, i32 0, i32 3, i32 14, i32 3, i32 0, i32 3, i32 -99, i32 3, i32 0, i32 3, i32 0, i32 3, i32 0, i32 3, i32 0, i32 0, ptr addrspace(1) null, i32 3, float 0.000000e+00, i32 4, double 0.000000e+00, i32 7, ptr null, i32 0, ptr addrspace(1) null, i32 0, ptr addrspace(1) null, i32 0, ptr addrspace(1) null, i32 7, ptr null, i32 7, ptr null, i32 0, ptr addrspace(1) null, i32 0, ptr addrspace(1) null, i32 0, ptr addrspace(1) null, i32 0, ptr addrspace(1) null, i32 7, ptr null, i32 7, ptr null, i32 7, ptr null, i32 7, ptr null) ]
+; CHECK-NEXT:    ret void
+;
 bb:
   br i1 %arg, label %bb1, label %bb4
 
Index: llvm/lib/Transforms/Utils/SimplifyCFG.cpp
===================================================================
--- llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1471,6 +1471,12 @@
   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<CallBase>(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();


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