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[ARM] Only produce qadd8b under hasV6Ops 

When compiling for a arm5te cpu from clang, the +dsp attribute is set.
This meant we could try and generate qadd8 instructions where we would
end up having no pattern. I've changed the condition here to be hasV6Ops
&& hasDSP, which is what other parts of ARMISelLowering seem to use for
similar instructions.

Fixed PR45677.

Differential Revision: https://reviews.llvm.org/D78877
This commit is contained in:
David Green 2020-04-26 21:58:58 +01:00
parent 1a0d466081
commit 8807139026
2 changed files with 2 additions and 1 deletions
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2
llvm/lib/Target/ARM/ARMISelLowering.cpp
View File

@ -4586,7 +4586,7 @@ SDValue ARMTargetLowering::LowerUnsignedALUO(SDValue Op,
static SDValue LowerSADDSUBSAT(SDValue Op, SelectionDAG &DAG,
const ARMSubtarget *Subtarget) {
EVT VT = Op.getValueType();
if (!Subtarget->hasDSP())
if (!Subtarget->hasV6Ops() || !Subtarget->hasDSP())
return SDValue();
if (!VT.isSimple())
return SDValue();

1
llvm/test/CodeGen/ARM/sadd_sat.ll
View File

@ -4,6 +4,7 @@
; RUN: llc < %s -mtriple=thumbv7em-none-eabi | FileCheck %s --check-prefix=CHECK-T2 --check-prefix=CHECK-T2DSP
; RUN: llc < %s -mtriple=armv5t-none-eabi | FileCheck %s --check-prefix=CHECK-ARM --check-prefix=CHECK-ARMNODPS
; RUN: llc < %s -mtriple=armv5te-none-eabi | FileCheck %s --check-prefix=CHECK-ARM --check-prefix=CHECK-ARMBASEDSP
; RUN: llc < %s -mtriple=armv5te-none-eabi -mattr=+dsp | FileCheck %s --check-prefix=CHECK-ARM --check-prefix=CHECK-ARMBASEDSP
; RUN: llc < %s -mtriple=armv6-none-eabi | FileCheck %s --check-prefix=CHECK-ARM --check-prefix=CHECK-ARMDSP
declare i4 @llvm.sadd.sat.i4(i4, i4)