Fix PR18572 - llc crash during GenericScheduler::initPolicy().

Generalized the heuristic that looks at the (very rough) size of the
register file before enabling regpressure tracking.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199766 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Trick 2014-01-21 21:27:37 +00:00
parent ce5f07f33c
commit 10afb02d48
2 changed files with 30 additions and 4 deletions

View File

@ -2531,10 +2531,16 @@ void GenericScheduler::initPolicy(MachineBasicBlock::iterator Begin,
// Avoid setting up the register pressure tracker for small regions to save
// compile time. As a rough heuristic, only track pressure when the number of
// schedulable instructions exceeds half the integer register file.
unsigned NIntRegs = Context->RegClassInfo->getNumAllocatableRegs(
TM.getTargetLowering()->getRegClassFor(MVT::i32));
RegionPolicy.ShouldTrackPressure = NumRegionInstrs > (NIntRegs / 2);
RegionPolicy.ShouldTrackPressure = true;
unsigned LegalIntVT = MVT::i32;
for (; LegalIntVT > (unsigned)MVT::i1; --LegalIntVT) {
if (TM.getTargetLowering()->isTypeLegal((MVT::SimpleValueType)LegalIntVT)) {
unsigned NIntRegs = Context->RegClassInfo->getNumAllocatableRegs(
TM.getTargetLowering()->getRegClassFor(
(MVT::SimpleValueType)LegalIntVT));
RegionPolicy.ShouldTrackPressure = NumRegionInstrs > (NIntRegs / 2);
}
}
// For generic targets, we default to bottom-up, because it's simpler and more
// compile-time optimizations have been implemented in that direction.

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@ -0,0 +1,20 @@
; RUN: llc < %s -mtriple=msp430-unknown-unknown -enable-misched | FileCheck %s
target datalayout = "e-p:16:16:16-i8:8:8-i16:16:16-i32:16:32-n8:16"
@y = common global i16 0, align 2
@x = common global i16 0, align 2
; Test that the MI Scheduler's initPolicy does not crash when i32 is
; unsupported. The content of the asm check below is unimportant. It
; only verifies that the code generator ran succesfully.
;
; CHECK-LABEL: @f
; CHECK: mov.w &y, &x
; CHECK: ret
define void @f() {
entry:
%0 = load i16* @y, align 2
store i16 %0, i16* @x, align 2
ret void
}