[llvm] 1dd94a2 - [RISCV] Add helper method for shift-and-add extensions (#158638)
via llvm-commits
llvm-commits at lists.llvm.org
Mon Sep 15 23:53:31 PDT 2025
Author: Piotr Fusik
Date: 2025-09-16T08:53:27+02:00
New Revision: 1dd94a23587b35ff5316a53fe7228c3fbe345c42
URL: https://github.com/llvm/llvm-project/commit/1dd94a23587b35ff5316a53fe7228c3fbe345c42
DIFF: https://github.com/llvm/llvm-project/commit/1dd94a23587b35ff5316a53fe7228c3fbe345c42.diff
LOG: [RISCV] Add helper method for shift-and-add extensions (#158638)
Not an NFC, as it improves consistency, enabling some cases
for XAndesPerf and XTheadBa.
Added:
Modified:
llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
llvm/lib/Target/RISCV/RISCVISelLowering.cpp
llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
llvm/lib/Target/RISCV/RISCVSubtarget.h
llvm/test/CodeGen/RISCV/rv32xtheadba.ll
llvm/test/CodeGen/RISCV/rv64xtheadba.ll
llvm/test/CodeGen/RISCV/xqciac.ll
Removed:
################################################################################
diff --git a/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp b/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
index c7f15415ebb91..dda6023b37f7b 100644
--- a/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
@@ -3204,9 +3204,7 @@ static bool isWorthFoldingIntoRegRegScale(const RISCVSubtarget &Subtarget,
// If we have a SHXADD instruction, prefer that over reassociating an ADDI.
assert(Shift.getOpcode() == ISD::SHL);
unsigned ShiftAmt = Shift.getConstantOperandVal(1);
- if ((ShiftAmt <= 3 &&
- (Subtarget.hasStdExtZba() || Subtarget.hasVendorXTHeadBa())) ||
- (ShiftAmt >= 4 && ShiftAmt <= 7 && Subtarget.hasVendorXqciac()))
+ if (Subtarget.hasShlAdd(ShiftAmt))
return false;
// All users of the ADDI should be load/store.
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 5485b916c2031..9d90eb0a65218 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -15349,11 +15349,9 @@ static SDValue combineBinOpToReduce(SDNode *N, SelectionDAG &DAG,
// (SLLI (QC.SHLADD x, y, c1 - c0), c0), if 4 <= (c1-c0) <=31.
static SDValue transformAddShlImm(SDNode *N, SelectionDAG &DAG,
const RISCVSubtarget &Subtarget) {
- const bool HasStdExtZba = Subtarget.hasStdExtZba();
- const bool HasVendorXAndesPerf = Subtarget.hasVendorXAndesPerf();
- const bool HasVendorXqciac = Subtarget.hasVendorXqciac();
- // Perform this optimization only in the zba/xandesperf/xqciac extension.
- if (!HasStdExtZba && !HasVendorXAndesPerf && !HasVendorXqciac)
+ // Perform this optimization only in the zba/xandesperf/xqciac/xtheadba
+ // extension.
+ if (!Subtarget.hasShlAdd(3))
return SDValue();
// Skip for vector types and larger types.
@@ -15379,16 +15377,7 @@ static SDValue transformAddShlImm(SDNode *N, SelectionDAG &DAG,
return SDValue();
int64_t Diff = std::abs(C0 - C1);
- bool IsShXaddDiff = Diff == 1 || Diff == 2 || Diff == 3;
- bool HasShXadd = HasStdExtZba || HasVendorXAndesPerf;
-
- // Skip if SH1ADD/SH2ADD/SH3ADD are not applicable.
- if ((!IsShXaddDiff && HasShXadd && !HasVendorXqciac) ||
- (IsShXaddDiff && !HasShXadd && HasVendorXqciac))
- return SDValue();
-
- // Skip if QC_SHLADD is not applicable.
- if (Diff == 0 || Diff > 31)
+ if (!Subtarget.hasShlAdd(Diff))
return SDValue();
// Build nodes.
@@ -15445,7 +15434,7 @@ static SDValue combineShlAddIAddImpl(SDNode *N, SDValue AddI, SDValue Other,
static SDValue combineShlAddIAdd(SDNode *N, SelectionDAG &DAG,
const RISCVSubtarget &Subtarget) {
// Perform this optimization only in the zba extension.
- if (!ReassocShlAddiAdd || !Subtarget.hasStdExtZba())
+ if (!ReassocShlAddiAdd || !Subtarget.hasShlAdd(3))
return SDValue();
// Skip for vector types and larger types.
@@ -16375,17 +16364,13 @@ static SDValue expandMul(SDNode *N, SelectionDAG &DAG,
if (Subtarget.hasVendorXqciac() && isInt<12>(CNode->getSExtValue()))
return SDValue();
- const bool HasShlAdd = Subtarget.hasStdExtZba() ||
- Subtarget.hasVendorXTHeadBa() ||
- Subtarget.hasVendorXAndesPerf();
-
// WARNING: The code below is knowingly incorrect with regards to undef semantics.
// We're adding additional uses of X here, and in principle, we should be freezing
// X before doing so. However, adding freeze here causes real regressions, and no
// other target properly freezes X in these cases either.
SDValue X = N->getOperand(0);
- if (HasShlAdd) {
+ if (Subtarget.hasShlAdd(3)) {
for (uint64_t Divisor : {3, 5, 9}) {
if (MulAmt % Divisor != 0)
continue;
@@ -21333,14 +21318,8 @@ bool RISCVTargetLowering::isDesirableToCommuteWithShift(
auto *C1 = dyn_cast<ConstantSDNode>(N0->getOperand(1));
auto *C2 = dyn_cast<ConstantSDNode>(N->getOperand(1));
- bool IsShXAdd =
- (Subtarget.hasStdExtZba() || Subtarget.hasVendorXAndesPerf()) && C2 &&
- C2->getZExtValue() >= 1 && C2->getZExtValue() <= 3;
- bool IsQCShlAdd = Subtarget.hasVendorXqciac() && C2 &&
- C2->getZExtValue() >= 4 && C2->getZExtValue() <= 31;
-
// Bail if we might break a sh{1,2,3}add/qc.shladd pattern.
- if ((IsShXAdd || IsQCShlAdd) && N->hasOneUse() &&
+ if (C2 && Subtarget.hasShlAdd(C2->getZExtValue()) && N->hasOneUse() &&
N->user_begin()->getOpcode() == ISD::ADD &&
!isUsedByLdSt(*N->user_begin(), nullptr) &&
!isa<ConstantSDNode>(N->user_begin()->getOperand(1)))
@@ -24398,7 +24377,7 @@ bool RISCVTargetLowering::decomposeMulByConstant(LLVMContext &Context, EVT VT,
return true;
// Optimize the MUL to (SH*ADD x, (SLLI x, bits)) if Imm is not simm12.
- if (Subtarget.hasStdExtZba() && !Imm.isSignedIntN(12) &&
+ if (Subtarget.hasShlAdd(3) && !Imm.isSignedIntN(12) &&
((Imm - 2).isPowerOf2() || (Imm - 4).isPowerOf2() ||
(Imm - 8).isPowerOf2()))
return true;
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp b/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
index d0bb57a3eaa13..f816112f70140 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
@@ -4492,7 +4492,7 @@ void RISCVInstrInfo::mulImm(MachineFunction &MF, MachineBasicBlock &MBB,
.addReg(DestReg, RegState::Kill)
.addImm(ShiftAmount)
.setMIFlag(Flag);
- } else if (STI.hasStdExtZba() &&
+ } else if (STI.hasShlAdd(3) &&
((Amount % 3 == 0 && isPowerOf2_64(Amount / 3)) ||
(Amount % 5 == 0 && isPowerOf2_64(Amount / 5)) ||
(Amount % 9 == 0 && isPowerOf2_64(Amount / 9)))) {
diff --git a/llvm/lib/Target/RISCV/RISCVSubtarget.h b/llvm/lib/Target/RISCV/RISCVSubtarget.h
index 0d9cd16a77937..aef084dd80d2a 100644
--- a/llvm/lib/Target/RISCV/RISCVSubtarget.h
+++ b/llvm/lib/Target/RISCV/RISCVSubtarget.h
@@ -209,6 +209,14 @@ class RISCVSubtarget : public RISCVGenSubtargetInfo {
hasShortForwardBranchOpt();
}
+ bool hasShlAdd(int64_t ShAmt) const {
+ if (ShAmt <= 0)
+ return false;
+ if (ShAmt <= 3)
+ return HasStdExtZba || HasVendorXAndesPerf || HasVendorXTHeadBa;
+ return ShAmt <= 31 && HasVendorXqciac;
+ }
+
bool is64Bit() const { return IsRV64; }
MVT getXLenVT() const {
return is64Bit() ? MVT::i64 : MVT::i32;
diff --git a/llvm/test/CodeGen/RISCV/rv32xtheadba.ll b/llvm/test/CodeGen/RISCV/rv32xtheadba.ll
index 0fc0adbfa83d9..0e4a5c07020ee 100644
--- a/llvm/test/CodeGen/RISCV/rv32xtheadba.ll
+++ b/llvm/test/CodeGen/RISCV/rv32xtheadba.ll
@@ -656,12 +656,18 @@ define i32 @add8192(i32 %a) {
}
define i32 @addshl_5_6(i32 %a, i32 %b) {
-; CHECK-LABEL: addshl_5_6:
-; CHECK: # %bb.0:
-; CHECK-NEXT: slli a0, a0, 5
-; CHECK-NEXT: slli a1, a1, 6
-; CHECK-NEXT: add a0, a0, a1
-; CHECK-NEXT: ret
+; RV32I-LABEL: addshl_5_6:
+; RV32I: # %bb.0:
+; RV32I-NEXT: slli a0, a0, 5
+; RV32I-NEXT: slli a1, a1, 6
+; RV32I-NEXT: add a0, a0, a1
+; RV32I-NEXT: ret
+;
+; RV32XTHEADBA-LABEL: addshl_5_6:
+; RV32XTHEADBA: # %bb.0:
+; RV32XTHEADBA-NEXT: th.addsl a0, a0, a1, 1
+; RV32XTHEADBA-NEXT: slli a0, a0, 5
+; RV32XTHEADBA-NEXT: ret
%c = shl i32 %a, 5
%d = shl i32 %b, 6
%e = add i32 %c, %d
@@ -669,12 +675,18 @@ define i32 @addshl_5_6(i32 %a, i32 %b) {
}
define i32 @addshl_5_7(i32 %a, i32 %b) {
-; CHECK-LABEL: addshl_5_7:
-; CHECK: # %bb.0:
-; CHECK-NEXT: slli a0, a0, 5
-; CHECK-NEXT: slli a1, a1, 7
-; CHECK-NEXT: add a0, a0, a1
-; CHECK-NEXT: ret
+; RV32I-LABEL: addshl_5_7:
+; RV32I: # %bb.0:
+; RV32I-NEXT: slli a0, a0, 5
+; RV32I-NEXT: slli a1, a1, 7
+; RV32I-NEXT: add a0, a0, a1
+; RV32I-NEXT: ret
+;
+; RV32XTHEADBA-LABEL: addshl_5_7:
+; RV32XTHEADBA: # %bb.0:
+; RV32XTHEADBA-NEXT: th.addsl a0, a0, a1, 2
+; RV32XTHEADBA-NEXT: slli a0, a0, 5
+; RV32XTHEADBA-NEXT: ret
%c = shl i32 %a, 5
%d = shl i32 %b, 7
%e = add i32 %c, %d
@@ -682,12 +694,18 @@ define i32 @addshl_5_7(i32 %a, i32 %b) {
}
define i32 @addshl_5_8(i32 %a, i32 %b) {
-; CHECK-LABEL: addshl_5_8:
-; CHECK: # %bb.0:
-; CHECK-NEXT: slli a0, a0, 5
-; CHECK-NEXT: slli a1, a1, 8
-; CHECK-NEXT: add a0, a0, a1
-; CHECK-NEXT: ret
+; RV32I-LABEL: addshl_5_8:
+; RV32I: # %bb.0:
+; RV32I-NEXT: slli a0, a0, 5
+; RV32I-NEXT: slli a1, a1, 8
+; RV32I-NEXT: add a0, a0, a1
+; RV32I-NEXT: ret
+;
+; RV32XTHEADBA-LABEL: addshl_5_8:
+; RV32XTHEADBA: # %bb.0:
+; RV32XTHEADBA-NEXT: th.addsl a0, a0, a1, 3
+; RV32XTHEADBA-NEXT: slli a0, a0, 5
+; RV32XTHEADBA-NEXT: ret
%c = shl i32 %a, 5
%d = shl i32 %b, 8
%e = add i32 %c, %d
diff --git a/llvm/test/CodeGen/RISCV/rv64xtheadba.ll b/llvm/test/CodeGen/RISCV/rv64xtheadba.ll
index d20fb66dbbeea..50bd22bf5fd69 100644
--- a/llvm/test/CodeGen/RISCV/rv64xtheadba.ll
+++ b/llvm/test/CodeGen/RISCV/rv64xtheadba.ll
@@ -1104,12 +1104,18 @@ define i64 @add8192(i64 %a) {
}
define signext i32 @addshl32_5_6(i32 signext %a, i32 signext %b) {
-; CHECK-LABEL: addshl32_5_6:
-; CHECK: # %bb.0:
-; CHECK-NEXT: slli a0, a0, 5
-; CHECK-NEXT: slli a1, a1, 6
-; CHECK-NEXT: addw a0, a0, a1
-; CHECK-NEXT: ret
+; RV64I-LABEL: addshl32_5_6:
+; RV64I: # %bb.0:
+; RV64I-NEXT: slli a0, a0, 5
+; RV64I-NEXT: slli a1, a1, 6
+; RV64I-NEXT: addw a0, a0, a1
+; RV64I-NEXT: ret
+;
+; RV64XTHEADBA-LABEL: addshl32_5_6:
+; RV64XTHEADBA: # %bb.0:
+; RV64XTHEADBA-NEXT: th.addsl a0, a0, a1, 1
+; RV64XTHEADBA-NEXT: slliw a0, a0, 5
+; RV64XTHEADBA-NEXT: ret
%c = shl i32 %a, 5
%d = shl i32 %b, 6
%e = add i32 %c, %d
@@ -1117,12 +1123,18 @@ define signext i32 @addshl32_5_6(i32 signext %a, i32 signext %b) {
}
define i64 @addshl64_5_6(i64 %a, i64 %b) {
-; CHECK-LABEL: addshl64_5_6:
-; CHECK: # %bb.0:
-; CHECK-NEXT: slli a0, a0, 5
-; CHECK-NEXT: slli a1, a1, 6
-; CHECK-NEXT: add a0, a0, a1
-; CHECK-NEXT: ret
+; RV64I-LABEL: addshl64_5_6:
+; RV64I: # %bb.0:
+; RV64I-NEXT: slli a0, a0, 5
+; RV64I-NEXT: slli a1, a1, 6
+; RV64I-NEXT: add a0, a0, a1
+; RV64I-NEXT: ret
+;
+; RV64XTHEADBA-LABEL: addshl64_5_6:
+; RV64XTHEADBA: # %bb.0:
+; RV64XTHEADBA-NEXT: th.addsl a0, a0, a1, 1
+; RV64XTHEADBA-NEXT: slli a0, a0, 5
+; RV64XTHEADBA-NEXT: ret
%c = shl i64 %a, 5
%d = shl i64 %b, 6
%e = add i64 %c, %d
@@ -1130,12 +1142,18 @@ define i64 @addshl64_5_6(i64 %a, i64 %b) {
}
define signext i32 @addshl32_5_7(i32 signext %a, i32 signext %b) {
-; CHECK-LABEL: addshl32_5_7:
-; CHECK: # %bb.0:
-; CHECK-NEXT: slli a0, a0, 5
-; CHECK-NEXT: slli a1, a1, 7
-; CHECK-NEXT: addw a0, a0, a1
-; CHECK-NEXT: ret
+; RV64I-LABEL: addshl32_5_7:
+; RV64I: # %bb.0:
+; RV64I-NEXT: slli a0, a0, 5
+; RV64I-NEXT: slli a1, a1, 7
+; RV64I-NEXT: addw a0, a0, a1
+; RV64I-NEXT: ret
+;
+; RV64XTHEADBA-LABEL: addshl32_5_7:
+; RV64XTHEADBA: # %bb.0:
+; RV64XTHEADBA-NEXT: th.addsl a0, a0, a1, 2
+; RV64XTHEADBA-NEXT: slliw a0, a0, 5
+; RV64XTHEADBA-NEXT: ret
%c = shl i32 %a, 5
%d = shl i32 %b, 7
%e = add i32 %c, %d
@@ -1143,12 +1161,18 @@ define signext i32 @addshl32_5_7(i32 signext %a, i32 signext %b) {
}
define i64 @addshl64_5_7(i64 %a, i64 %b) {
-; CHECK-LABEL: addshl64_5_7:
-; CHECK: # %bb.0:
-; CHECK-NEXT: slli a0, a0, 5
-; CHECK-NEXT: slli a1, a1, 7
-; CHECK-NEXT: add a0, a0, a1
-; CHECK-NEXT: ret
+; RV64I-LABEL: addshl64_5_7:
+; RV64I: # %bb.0:
+; RV64I-NEXT: slli a0, a0, 5
+; RV64I-NEXT: slli a1, a1, 7
+; RV64I-NEXT: add a0, a0, a1
+; RV64I-NEXT: ret
+;
+; RV64XTHEADBA-LABEL: addshl64_5_7:
+; RV64XTHEADBA: # %bb.0:
+; RV64XTHEADBA-NEXT: th.addsl a0, a0, a1, 2
+; RV64XTHEADBA-NEXT: slli a0, a0, 5
+; RV64XTHEADBA-NEXT: ret
%c = shl i64 %a, 5
%d = shl i64 %b, 7
%e = add i64 %c, %d
@@ -1156,12 +1180,18 @@ define i64 @addshl64_5_7(i64 %a, i64 %b) {
}
define signext i32 @addshl32_5_8(i32 signext %a, i32 signext %b) {
-; CHECK-LABEL: addshl32_5_8:
-; CHECK: # %bb.0:
-; CHECK-NEXT: slli a0, a0, 5
-; CHECK-NEXT: slli a1, a1, 8
-; CHECK-NEXT: addw a0, a0, a1
-; CHECK-NEXT: ret
+; RV64I-LABEL: addshl32_5_8:
+; RV64I: # %bb.0:
+; RV64I-NEXT: slli a0, a0, 5
+; RV64I-NEXT: slli a1, a1, 8
+; RV64I-NEXT: addw a0, a0, a1
+; RV64I-NEXT: ret
+;
+; RV64XTHEADBA-LABEL: addshl32_5_8:
+; RV64XTHEADBA: # %bb.0:
+; RV64XTHEADBA-NEXT: th.addsl a0, a0, a1, 3
+; RV64XTHEADBA-NEXT: slliw a0, a0, 5
+; RV64XTHEADBA-NEXT: ret
%c = shl i32 %a, 5
%d = shl i32 %b, 8
%e = add i32 %c, %d
@@ -1169,12 +1199,18 @@ define signext i32 @addshl32_5_8(i32 signext %a, i32 signext %b) {
}
define i64 @addshl64_5_8(i64 %a, i64 %b) {
-; CHECK-LABEL: addshl64_5_8:
-; CHECK: # %bb.0:
-; CHECK-NEXT: slli a0, a0, 5
-; CHECK-NEXT: slli a1, a1, 8
-; CHECK-NEXT: add a0, a0, a1
-; CHECK-NEXT: ret
+; RV64I-LABEL: addshl64_5_8:
+; RV64I: # %bb.0:
+; RV64I-NEXT: slli a0, a0, 5
+; RV64I-NEXT: slli a1, a1, 8
+; RV64I-NEXT: add a0, a0, a1
+; RV64I-NEXT: ret
+;
+; RV64XTHEADBA-LABEL: addshl64_5_8:
+; RV64XTHEADBA: # %bb.0:
+; RV64XTHEADBA-NEXT: th.addsl a0, a0, a1, 3
+; RV64XTHEADBA-NEXT: slli a0, a0, 5
+; RV64XTHEADBA-NEXT: ret
%c = shl i64 %a, 5
%d = shl i64 %b, 8
%e = add i64 %c, %d
@@ -1192,9 +1228,8 @@ define i64 @sh6_sh3_add1(i64 noundef %x, i64 noundef %y, i64 noundef %z) {
;
; RV64XTHEADBA-LABEL: sh6_sh3_add1:
; RV64XTHEADBA: # %bb.0: # %entry
-; RV64XTHEADBA-NEXT: slli a1, a1, 6
-; RV64XTHEADBA-NEXT: th.addsl a1, a1, a2, 3
-; RV64XTHEADBA-NEXT: add a0, a1, a0
+; RV64XTHEADBA-NEXT: th.addsl a1, a2, a1, 3
+; RV64XTHEADBA-NEXT: th.addsl a0, a0, a1, 3
; RV64XTHEADBA-NEXT: ret
entry:
%shl = shl i64 %z, 3
@@ -1238,9 +1273,8 @@ define i64 @sh6_sh3_add3(i64 noundef %x, i64 noundef %y, i64 noundef %z) {
;
; RV64XTHEADBA-LABEL: sh6_sh3_add3:
; RV64XTHEADBA: # %bb.0: # %entry
-; RV64XTHEADBA-NEXT: slli a1, a1, 6
-; RV64XTHEADBA-NEXT: th.addsl a1, a1, a2, 3
-; RV64XTHEADBA-NEXT: add a0, a0, a1
+; RV64XTHEADBA-NEXT: th.addsl a1, a2, a1, 3
+; RV64XTHEADBA-NEXT: th.addsl a0, a0, a1, 3
; RV64XTHEADBA-NEXT: ret
entry:
%shl = shl i64 %z, 3
diff --git a/llvm/test/CodeGen/RISCV/xqciac.ll b/llvm/test/CodeGen/RISCV/xqciac.ll
index c76e1a9d64f17..ec83fd7a28f32 100644
--- a/llvm/test/CodeGen/RISCV/xqciac.ll
+++ b/llvm/test/CodeGen/RISCV/xqciac.ll
@@ -361,8 +361,8 @@ define dso_local i32 @shladdc1c2(i32 %a, i32 %b) local_unnamed_addr #0 {
;
; RV32IMXQCIAC-LABEL: shladdc1c2:
; RV32IMXQCIAC: # %bb.0: # %entry
-; RV32IMXQCIAC-NEXT: qc.shladd a0, a0, a1, 5
-; RV32IMXQCIAC-NEXT: slli a0, a0, 26
+; RV32IMXQCIAC-NEXT: slli a1, a1, 26
+; RV32IMXQCIAC-NEXT: qc.shladd a0, a0, a1, 31
; RV32IMXQCIAC-NEXT: ret
;
; RV32IZBAMXQCIAC-LABEL: shladdc1c2:
More information about the llvm-commits
mailing list