Change how we rewind instructions in Air's O0 register allocator
https://bugs.webkit.org/show_bug.cgi?id=241687
Reviewed by Mark Lam.
* Source/JavaScriptCore/b3/air/AirAllocateRegistersAndStackAndGenerateCode.cpp:
(JSC::B3::Air::GenerateAndAllocateRegisters::generate):
Canonical link: https://commits.webkit.org/251611@main
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@295606 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/Source/JavaScriptCore/b3/air/AirAllocateRegistersAndStackAndGenerateCode.cpp b/Source/JavaScriptCore/b3/air/AirAllocateRegistersAndStackAndGenerateCode.cpp
index f85f072..7585f34 100644
--- a/Source/JavaScriptCore/b3/air/AirAllocateRegistersAndStackAndGenerateCode.cpp
+++ b/Source/JavaScriptCore/b3/air/AirAllocateRegistersAndStackAndGenerateCode.cpp
@@ -590,6 +590,7 @@
context.indexInBlock = instIndex;
Inst& inst = block->at(instIndex);
+ Inst instCopy = inst;
m_namedUsedRegs = RegisterSet();
m_namedDefdRegs = RegisterSet();
@@ -753,26 +754,7 @@
if (!success) {
RELEASE_ASSERT(!isReplayingSameInst); // We should only need to do the below at most once per inst.
- // We need to capture the register state before we start spilling things
- // since we may have multiple arguments that are the same register.
- IndexMap<Reg, Tmp> allocationSnapshot = currentAllocation;
-
- // We rewind this Inst to be in its previous state, however, if any arg admits stack,
- // we move to providing that arg in stack form. This will allow us to fully allocate
- // this inst when we rewind.
- inst.forEachTmpFast([&] (Tmp& tmp) {
- if (!tmp.isReg())
- return;
- if (isDisallowedRegister(tmp.reg()))
- return;
- Tmp originalTmp = allocationSnapshot[tmp.reg()];
- if (originalTmp.isReg()) {
- ASSERT(tmp.reg() == originalTmp.reg());
- // This means this Inst referred to this reg directly. We leave these as is.
- return;
- }
- tmp = originalTmp;
- });
+ inst = instCopy;
inst.forEachArg([&] (Arg& arg, Arg::Role, Bank, Width) {
if (arg.isTmp() && !arg.tmp().isReg() && inst.admitsStack(arg)) {
Tmp tmp = arg.tmp();
