[llvm] r283329 - Revert r282920 "X86: Allow conditional tail calls in Win64 "leaf" functions (PR26302)"
Hans Wennborg via llvm-commits
llvm-commits at lists.llvm.org
Wed Oct 5 08:39:27 PDT 2016
Author: hans
Date: Wed Oct 5 10:39:27 2016
New Revision: 283329
URL: http://llvm.org/viewvc/llvm-project?rev=283329&view=rev
Log:
Revert r282920 "X86: Allow conditional tail calls in Win64 "leaf" functions (PR26302)"
This is suspected to cause a miscompile in Chromium. Reverting while
investigating.
Modified:
llvm/trunk/lib/Target/X86/X86ExpandPseudo.cpp
llvm/trunk/lib/Target/X86/X86InstrInfo.cpp
llvm/trunk/test/CodeGen/X86/conditional-tailcall.ll
Modified: llvm/trunk/lib/Target/X86/X86ExpandPseudo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ExpandPseudo.cpp?rev=283329&r1=283328&r2=283329&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ExpandPseudo.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ExpandPseudo.cpp Wed Oct 5 10:39:27 2016
@@ -122,9 +122,8 @@ bool X86ExpandPseudo::ExpandMI(MachineBa
Op = X86::TAILJMPd_CC;
break;
case X86::TCRETURNdi64cc:
- assert(!MBB.getParent()->hasWinCFI() &&
- "Conditional tail calls confuse "
- "the Win64 unwinder.");
+ assert(!IsWin64 && "Conditional tail calls confuse the Win64 unwinder.");
+ // TODO: We could do it for Win64 "leaf" functions though; PR30337.
Op = X86::TAILJMPd64_CC;
break;
default:
Modified: llvm/trunk/lib/Target/X86/X86InstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrInfo.cpp?rev=283329&r1=283328&r2=283329&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86InstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86InstrInfo.cpp Wed Oct 5 10:39:27 2016
@@ -4277,9 +4277,9 @@ bool X86InstrInfo::canMakeTailCallCondit
return false;
}
- const MachineFunction *MF = TailCall.getParent()->getParent();
- if (Subtarget.isTargetWin64() && MF->hasWinCFI()) {
+ if (Subtarget.isTargetWin64()) {
// Conditional tail calls confuse the Win64 unwinder.
+ // TODO: Allow them for "leaf" functions; PR30337.
return false;
}
@@ -4289,7 +4289,8 @@ bool X86InstrInfo::canMakeTailCallCondit
return false;
}
- const X86MachineFunctionInfo *X86FI = MF->getInfo<X86MachineFunctionInfo>();
+ const X86MachineFunctionInfo *X86FI =
+ TailCall.getParent()->getParent()->getInfo<X86MachineFunctionInfo>();
if (X86FI->getTCReturnAddrDelta() != 0 ||
TailCall.getOperand(1).getImm() != 0) {
// A conditional tail call cannot do any stack adjustment.
Modified: llvm/trunk/test/CodeGen/X86/conditional-tailcall.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/conditional-tailcall.ll?rev=283329&r1=283328&r2=283329&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/conditional-tailcall.ll (original)
+++ llvm/trunk/test/CodeGen/X86/conditional-tailcall.ll Wed Oct 5 10:39:27 2016
@@ -1,6 +1,5 @@
-; RUN: llc < %s -mtriple=i686-linux -show-mc-encoding | FileCheck -check-prefix=CHECK %s
-; RUN: llc < %s -mtriple=x86_64-linux -show-mc-encoding | FileCheck -check-prefix=CHECK %s
-; RUN: llc < %s -mtriple=x86_64-win32 -show-mc-encoding | FileCheck -check-prefix=CHECK -check-prefix=WIN64 %s
+; RUN: llc < %s -mtriple=i686-linux -show-mc-encoding | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64-linux -show-mc-encoding | FileCheck %s
declare void @foo()
declare void @bar()
@@ -24,28 +23,6 @@ bb2:
; CHECK: jmp foo
}
-define void @f_non_leaf(i32 %x, i32 %y) optsize {
-entry:
- ; Force %ebx to be spilled on the stack, turning this into
- ; not a "leaf" function for Win64.
- tail call void asm sideeffect "", "~{ebx}"()
-
- %p = icmp eq i32 %x, %y
- br i1 %p, label %bb1, label %bb2
-bb1:
- tail call void @foo()
- ret void
-bb2:
- tail call void @bar()
- ret void
-
-; CHECK-LABEL: f_non_leaf:
-; WIN64-NOT: je foo
-; WIN64-NOT: jne bar
-; WIN64: jne
-; WIN64: jmp foo
-; WIN64: jmp bar
-}
declare x86_thiscallcc zeroext i1 @baz(i8*, i32)
define x86_thiscallcc zeroext i1 @BlockPlacementTest(i8* %this, i32 %x) optsize {
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