[llvm] r367700 - [AArch64][GlobalISel] Support the neg_addsub_shifted_imm32 pattern
Jessica Paquette via llvm-commits
llvm-commits at lists.llvm.org
Fri Aug 2 11:12:53 PDT 2019
Author: paquette
Date: Fri Aug 2 11:12:53 2019
New Revision: 367700
URL: http://llvm.org/viewvc/llvm-project?rev=367700&view=rev
Log:
[AArch64][GlobalISel] Support the neg_addsub_shifted_imm32 pattern
Add an equivalent ComplexRendererFns function for SelectNegArithImmed. This
allows us to select immediate adds of -1 by turning them into subtracts.
Update select-binop.mir to show that the pattern works.
Differential Revision: https://reviews.llvm.org/D65460
Modified:
llvm/trunk/lib/Target/AArch64/AArch64InstrFormats.td
llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp
llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-binop.mir
Modified: llvm/trunk/lib/Target/AArch64/AArch64InstrFormats.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64InstrFormats.td?rev=367700&r1=367699&r2=367700&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64InstrFormats.td (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64InstrFormats.td Fri Aug 2 11:12:53 2019
@@ -885,6 +885,14 @@ class neg_addsub_shifted_imm<ValueType T
def neg_addsub_shifted_imm32 : neg_addsub_shifted_imm<i32>;
def neg_addsub_shifted_imm64 : neg_addsub_shifted_imm<i64>;
+def gi_neg_addsub_shifted_imm32 :
+ GIComplexOperandMatcher<s32, "selectNegArithImmed">,
+ GIComplexPatternEquiv<neg_addsub_shifted_imm32>;
+
+def gi_neg_addsub_shifted_imm64 :
+ GIComplexOperandMatcher<s64, "selectNegArithImmed">,
+ GIComplexPatternEquiv<neg_addsub_shifted_imm64>;
+
// An extend operand:
// {5-3} - extend type
// {2-0} - imm3
Modified: llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp?rev=367700&r1=367699&r2=367700&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp Fri Aug 2 11:12:53 2019
@@ -162,7 +162,9 @@ private:
ComplexRendererFns selectShiftA_64(const MachineOperand &Root) const;
ComplexRendererFns selectShiftB_64(const MachineOperand &Root) const;
+ ComplexRendererFns select12BitValueWithLeftShift(uint64_t Immed) const;
ComplexRendererFns selectArithImmed(MachineOperand &Root) const;
+ ComplexRendererFns selectNegArithImmed(MachineOperand &Root) const;
ComplexRendererFns selectAddrModeUnscaled(MachineOperand &Root,
unsigned Size) const;
@@ -4081,6 +4083,30 @@ AArch64InstructionSelector::selectShiftB
return {{[=](MachineInstrBuilder &MIB) { MIB.addImm(Enc); }}};
}
+/// Helper to select an immediate value that can be represented as a 12-bit
+/// value shifted left by either 0 or 12. If it is possible to do so, return
+/// the immediate and shift value. If not, return None.
+///
+/// Used by selectArithImmed and selectNegArithImmed.
+InstructionSelector::ComplexRendererFns
+AArch64InstructionSelector::select12BitValueWithLeftShift(
+ uint64_t Immed) const {
+ unsigned ShiftAmt;
+ if (Immed >> 12 == 0) {
+ ShiftAmt = 0;
+ } else if ((Immed & 0xfff) == 0 && Immed >> 24 == 0) {
+ ShiftAmt = 12;
+ Immed = Immed >> 12;
+ } else
+ return None;
+
+ unsigned ShVal = AArch64_AM::getShifterImm(AArch64_AM::LSL, ShiftAmt);
+ return {{
+ [=](MachineInstrBuilder &MIB) { MIB.addImm(Immed); },
+ [=](MachineInstrBuilder &MIB) { MIB.addImm(ShVal); },
+ }};
+}
+
/// SelectArithImmed - Select an immediate value that can be represented as
/// a 12-bit value shifted left by either 0 or 12. If so, return true with
/// Val set to the 12-bit value and Shift set to the shifter operand.
@@ -4094,22 +4120,41 @@ AArch64InstructionSelector::selectArithI
auto MaybeImmed = getImmedFromMO(Root);
if (MaybeImmed == None)
return None;
+ return select12BitValueWithLeftShift(*MaybeImmed);
+}
+
+/// SelectNegArithImmed - As above, but negates the value before trying to
+/// select it.
+InstructionSelector::ComplexRendererFns
+AArch64InstructionSelector::selectNegArithImmed(MachineOperand &Root) const {
+ // We need a register here, because we need to know if we have a 64 or 32
+ // bit immediate.
+ if (!Root.isReg())
+ return None;
+ auto MaybeImmed = getImmedFromMO(Root);
+ if (MaybeImmed == None)
+ return None;
uint64_t Immed = *MaybeImmed;
- unsigned ShiftAmt;
- if (Immed >> 12 == 0) {
- ShiftAmt = 0;
- } else if ((Immed & 0xfff) == 0 && Immed >> 24 == 0) {
- ShiftAmt = 12;
- Immed = Immed >> 12;
- } else
+ // This negation is almost always valid, but "cmp wN, #0" and "cmn wN, #0"
+ // have the opposite effect on the C flag, so this pattern mustn't match under
+ // those circumstances.
+ if (Immed == 0)
return None;
- unsigned ShVal = AArch64_AM::getShifterImm(AArch64_AM::LSL, ShiftAmt);
- return {{
- [=](MachineInstrBuilder &MIB) { MIB.addImm(Immed); },
- [=](MachineInstrBuilder &MIB) { MIB.addImm(ShVal); },
- }};
+ // Check if we're dealing with a 32-bit type on the root or a 64-bit type on
+ // the root.
+ MachineRegisterInfo &MRI = Root.getParent()->getMF()->getRegInfo();
+ if (MRI.getType(Root.getReg()).getSizeInBits() == 32)
+ Immed = ~((uint32_t)Immed) + 1;
+ else
+ Immed = ~Immed + 1ULL;
+
+ if (Immed & 0xFFFFFFFFFF000000ULL)
+ return None;
+
+ Immed &= 0xFFFFFFULL;
+ return select12BitValueWithLeftShift(Immed);
}
/// Return true if it is worth folding MI into an extended register. That is,
Modified: llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-binop.mir
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-binop.mir?rev=367700&r1=367699&r2=367700&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-binop.mir (original)
+++ llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-binop.mir Fri Aug 2 11:12:53 2019
@@ -10,6 +10,13 @@
define void @add_imm_s32_gpr() { ret void }
define void @add_imm_s64_gpr() { ret void }
+ define void @add_neg_s32_gpr() { ret void }
+ define void @add_neg_s64_gpr() { ret void }
+ define void @add_neg_invalid_immed_s32() { ret void }
+ define void @add_neg_invalid_immed_s64() { ret void }
+ define void @add_imm_0_s32() { ret void }
+ define void @add_imm_0_s64() { ret void }
+
define void @add_imm_s32_gpr_bb() { ret void }
define void @sub_s32_gpr() { ret void }
@@ -159,6 +166,154 @@ body: |
%2(s64) = G_ADD %0, %1
$x0 = COPY %2(s64)
...
+
+---
+name: add_neg_s32_gpr
+legalized: true
+regBankSelected: true
+
+registers:
+ - { id: 0, class: gpr }
+ - { id: 1, class: gpr }
+ - { id: 2, class: gpr }
+
+body: |
+ bb.0:
+ liveins: $w1, $w2
+ ; We should be able to turn the ADD into a SUB.
+ ; CHECK-LABEL: name: add_neg_s32_gpr
+ ; CHECK: [[COPY:%[0-9]+]]:gpr32sp = COPY $w1
+ ; CHECK: [[SUBSWri:%[0-9]+]]:gpr32 = SUBSWri [[COPY]], 1, 0, implicit-def $nzcv
+ ; CHECK: $w2 = COPY [[SUBSWri]]
+ %0(s32) = COPY $w1
+ %1(s32) = G_CONSTANT i32 -1
+ %2(s32) = G_ADD %0, %1
+ $w2 = COPY %2(s32)
+...
+
+---
+name: add_neg_s64_gpr
+legalized: true
+regBankSelected: true
+
+registers:
+ - { id: 0, class: gpr }
+ - { id: 1, class: gpr }
+ - { id: 2, class: gpr }
+
+body: |
+ bb.0:
+ liveins: $x0, $x1
+ ; We should be able to turn the ADD into a SUB.
+ ; CHECK-LABEL: name: add_neg_s64_gpr
+ ; CHECK: [[COPY:%[0-9]+]]:gpr64sp = COPY $x0
+ ; CHECK: [[SUBSXri:%[0-9]+]]:gpr64 = SUBSXri [[COPY]], 1, 0, implicit-def $nzcv
+ ; CHECK: $x0 = COPY [[SUBSXri]]
+ %0(s64) = COPY $x0
+ %1(s64) = G_CONSTANT i64 -1
+ %2(s64) = G_ADD %0, %1
+ $x0 = COPY %2(s64)
+...
+
+---
+name: add_neg_invalid_immed_s32
+legalized: true
+regBankSelected: true
+
+registers:
+ - { id: 0, class: gpr }
+ - { id: 1, class: gpr }
+ - { id: 2, class: gpr }
+
+body: |
+ bb.0:
+ liveins: $x0, $x1
+ ; We can't select this if the value is out of range.
+ ; CHECK-LABEL: name: add_neg_invalid_immed_s32
+ ; CHECK: [[COPY:%[0-9]+]]:gpr64 = COPY $x0
+ ; CHECK: [[MOVi64imm:%[0-9]+]]:gpr64 = MOVi64imm -5000
+ ; CHECK: [[ADDXrr:%[0-9]+]]:gpr64 = ADDXrr [[COPY]], [[MOVi64imm]]
+ ; CHECK: $x0 = COPY [[ADDXrr]]
+ %0(s64) = COPY $x0
+ %1(s64) = G_CONSTANT i64 -5000
+ %2(s64) = G_ADD %0, %1
+ $x0 = COPY %2(s64)
+...
+
+---
+name: add_neg_invalid_immed_s64
+legalized: true
+regBankSelected: true
+
+registers:
+ - { id: 0, class: gpr }
+ - { id: 1, class: gpr }
+ - { id: 2, class: gpr }
+
+body: |
+ bb.0:
+ liveins: $x0, $x1
+ ; We can't select this if the value is out of range.
+ ; CHECK-LABEL: name: add_neg_invalid_immed_s64
+ ; CHECK: [[COPY:%[0-9]+]]:gpr64 = COPY $x0
+ ; CHECK: [[MOVi64imm:%[0-9]+]]:gpr64 = MOVi64imm -5000
+ ; CHECK: [[ADDXrr:%[0-9]+]]:gpr64 = ADDXrr [[COPY]], [[MOVi64imm]]
+ ; CHECK: $x0 = COPY [[ADDXrr]]
+ %0(s64) = COPY $x0
+ %1(s64) = G_CONSTANT i64 -5000
+ %2(s64) = G_ADD %0, %1
+ $x0 = COPY %2(s64)
+...
+
+---
+name: add_imm_0_s32
+legalized: true
+regBankSelected: true
+
+registers:
+ - { id: 0, class: gpr }
+ - { id: 1, class: gpr }
+ - { id: 2, class: gpr }
+
+body: |
+ bb.0:
+ liveins: $x0, $x1
+ ; We shouldn't get a SUB here, because "cmp wN, $0" and "cmp wN, #0" have
+ ; opposite effects on the C flag.
+ ; CHECK-LABEL: name: add_imm_0_s32
+ ; CHECK: [[COPY:%[0-9]+]]:gpr64sp = COPY $x0
+ ; CHECK: [[ADDXri:%[0-9]+]]:gpr64sp = ADDXri [[COPY]], 0, 0
+ ; CHECK: $x0 = COPY [[ADDXri]]
+ %0(s64) = COPY $x0
+ %1(s64) = G_CONSTANT i64 0
+ %2(s64) = G_ADD %0, %1
+ $x0 = COPY %2(s64)
+...
+
+---
+name: add_imm_0_s64
+legalized: true
+regBankSelected: true
+
+registers:
+ - { id: 0, class: gpr }
+ - { id: 1, class: gpr }
+ - { id: 2, class: gpr }
+
+body: |
+ bb.0:
+ liveins: $x0, $x1
+ ; We shouldn't get a SUB here, because "cmp xN, $0" and "cmp xN, #0" have
+ ; opposite effects on the C flag.
+ ; CHECK-LABEL: name: add_imm_0_s64
+ ; CHECK: [[COPY:%[0-9]+]]:gpr64sp = COPY $x0
+ ; CHECK: [[ADDXri:%[0-9]+]]:gpr64sp = ADDXri [[COPY]], 0, 0
+ ; CHECK: $x0 = COPY [[ADDXri]]
+ %0(s64) = COPY $x0
+ %1(s64) = G_CONSTANT i64 0
+ %2(s64) = G_ADD %0, %1
+ $x0 = COPY %2(s64)
+...
---
name: add_imm_s32_gpr_bb
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