[PATCH] D52032: [ARM] Fix FixConsts for ARMCodeGenPrepare
Sam Parker via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Thu Sep 13 06:52:27 PDT 2018
samparker created this revision.
samparker added a reviewer: SjoerdMeijer.
Herald added a reviewer: javed.absar.
Herald added subscribers: chrib, kristof.beyls.
Part of FixConsts wrongly assumes either a 8- or 16-bit constant which can result in the wrong constants being generated during promotion.
https://reviews.llvm.org/D52032
Files:
lib/Target/ARM/ARMCodeGenPrepare.cpp
test/CodeGen/ARM/arm-cgp-icmps.ll
Index: test/CodeGen/ARM/arm-cgp-icmps.ll
===================================================================
--- test/CodeGen/ARM/arm-cgp-icmps.ll
+++ test/CodeGen/ARM/arm-cgp-icmps.ll
@@ -1,4 +1,4 @@
-; RUN: llc -mtriple=thumbv8.main -mcpu=cortex-m33 %s -arm-disable-cgp=false -o - | FileCheck %s --check-prefix=CHECK-COMMON --check-prefix=CHECK-NODSP
+; RUN: llc -mtriple=thumbv8m.main -mcpu=cortex-m33 %s -arm-disable-cgp=false -o - | FileCheck %s --check-prefix=CHECK-COMMON --check-prefix=CHECK-NODSP
; RUN: llc -mtriple=thumbv7em %s -arm-disable-cgp=false -arm-enable-scalar-dsp=true -o - | FileCheck %s --check-prefix=CHECK-COMMON --check-prefix=CHECK-DSP
; RUN: llc -mtriple=thumbv8 %s -arm-disable-cgp=false -arm-enable-scalar-dsp=true -arm-enable-scalar-dsp-imms=true -o - | FileCheck %s --check-prefix=CHECK-COMMON --check-prefix=CHECK-DSP-IMM
@@ -279,3 +279,12 @@
ret i32 %res
}
+; CHECK-COMMON-LABEL: icmp_i15
+; CHECK-COMMON: movw [[MINUS_ONE:r[0-9]+]], #32767
+define i32 @icmp_i15(i15 zeroext %arg0, i15 zeroext %arg1) {
+ %xor = xor i15 %arg0, -1
+ %cmp = icmp eq i15 %xor, %arg1
+ %res = select i1 %cmp, i32 21, i32 42
+ ret i32 %res
+}
+
Index: lib/Target/ARM/ARMCodeGenPrepare.cpp
===================================================================
--- lib/Target/ARM/ARMCodeGenPrepare.cpp
+++ lib/Target/ARM/ARMCodeGenPrepare.cpp
@@ -271,13 +271,6 @@
return true;
}
- // Otherwise, if an instruction is using a negative immediate we will need
- // to fix it up during the promotion.
- for (auto &Op : I->operands()) {
- if (auto *Const = dyn_cast<ConstantInt>(Op))
- if (Const->isNegative())
- return false;
- }
return false;
}
@@ -370,19 +363,9 @@
};
auto FixConst = [&](ConstantInt *Const, Instruction *I) {
- Constant *NewConst = nullptr;
- if (isSafeOverflow(I)) {
- NewConst = (Const->isNegative()) ?
- ConstantExpr::getSExt(Const, ExtTy) :
- ConstantExpr::getZExt(Const, ExtTy);
- } else {
- uint64_t NewVal = *Const->getValue().getRawData();
- if (Const->getType() == Type::getInt16Ty(Ctx))
- NewVal &= 0xFFFF;
- else
- NewVal &= 0xFF;
- NewConst = ConstantInt::get(ExtTy, NewVal);
- }
+ Constant *NewConst = isSafeOverflow(I) && Const->isNegative() ?
+ ConstantExpr::getSExt(Const, ExtTy) :
+ ConstantExpr::getZExt(Const, ExtTy);
I->replaceUsesOfWith(Const, NewConst);
};
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