[clang] c047b9c - [RISCV][P-ext] Add scalar mulq(r) intrinsics (#232316)

via cfe-commits cfe-commits at lists.llvm.org
Thu Oct 15 23:06:51 PDT 2026


Author: SiHuaN
Date: 2026-10-16T14:06:43+08:00
New Revision: c047b9cfbd1b08da1d9f6b8937380913fa68c11b

URL: https://github.com/llvm/llvm-project/commit/c047b9cfbd1b08da1d9f6b8937380913fa68c11b
DIFF: https://github.com/llvm/llvm-project/commit/c047b9cfbd1b08da1d9f6b8937380913fa68c11b.diff

LOG: [RISCV][P-ext] Add scalar mulq(r) intrinsics (#232316)

Add the scalar "Q-format" Multiplication intrinsics:
https://github.com/riscv/riscv-p-spec/blob/master/P-ext-intrinsics.adoc#q-format-multiplication

- `__riscv_mulq_i32`
- `__riscv_mulqr_i32`

RV32 selects `mulq`/`mulqr` directly. RV64 has no scalar forms, so the
intrinsics use `pmulq.w`/`pmulqr.w` on the low words, the same way as
the scalar `aadd`/`asub` intrinsics (#230710).

Added: 
    

Modified: 
    clang/include/clang/Basic/BuiltinsRISCV.td
    clang/lib/CodeGen/TargetBuiltins/RISCV.cpp
    clang/lib/Headers/riscv_packed_simd.h
    clang/test/CodeGen/RISCV/rvp-intrinsics.c
    cross-project-tests/intrinsic-header-tests/riscv_packed_simd.c
    llvm/include/llvm/IR/IntrinsicsRISCV.td
    llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    llvm/test/CodeGen/RISCV/rv32p.ll
    llvm/test/CodeGen/RISCV/rv64p.ll

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/Basic/BuiltinsRISCV.td b/clang/include/clang/Basic/BuiltinsRISCV.td
index d496333952052..2d6466f261913 100644
--- a/clang/include/clang/Basic/BuiltinsRISCV.td
+++ b/clang/include/clang/Basic/BuiltinsRISCV.td
@@ -279,6 +279,10 @@ def mulhru_u32 : RISCVBuiltin<"uint32_t(uint32_t, uint32_t)">;
 def mulhsu_i32 : RISCVBuiltin<"int32_t(int32_t, uint32_t)">;
 def mulhrsu_i32 : RISCVBuiltin<"int32_t(int32_t, uint32_t)">;
 
+// Scalar "Q-format" Multiplication
+def mulq_i32 : RISCVBuiltin<"int32_t(int32_t, int32_t)">;
+def mulqr_i32 : RISCVBuiltin<"int32_t(int32_t, int32_t)">;
+
 // Packed Multiply High (32-bit)
 def pmulh_i16x2 : RISCVBuiltin<"_Vector<2, short>(_Vector<2, short>, _Vector<2, short>)">;
 def pmulhr_i16x2 : RISCVBuiltin<"_Vector<2, short>(_Vector<2, short>, _Vector<2, short>)">;

diff  --git a/clang/lib/CodeGen/TargetBuiltins/RISCV.cpp b/clang/lib/CodeGen/TargetBuiltins/RISCV.cpp
index e6f1d3c59b946..08c237196d5a0 100644
--- a/clang/lib/CodeGen/TargetBuiltins/RISCV.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/RISCV.cpp
@@ -1719,6 +1719,14 @@ Value *CodeGenFunction::EmitRISCVBuiltinExpr(unsigned BuiltinID,
     break;
   }
 
+  // Scalar "Q-format" Multiplication
+  case RISCV::BI__builtin_riscv_mulq_i32:
+    ID = Intrinsic::riscv_mulq_i32;
+    break;
+  case RISCV::BI__builtin_riscv_mulqr_i32:
+    ID = Intrinsic::riscv_mulqr_i32;
+    break;
+
   // Packed "Q-format" Multiply with Widening Accumulate
   case RISCV::BI__builtin_riscv_pmqwacc_i32x2:
   case RISCV::BI__builtin_riscv_pmqrwacc_i32x2: {

diff  --git a/clang/lib/Headers/riscv_packed_simd.h b/clang/lib/Headers/riscv_packed_simd.h
index 4c3599e8f192b..71bde1f17e6ca 100644
--- a/clang/lib/Headers/riscv_packed_simd.h
+++ b/clang/lib/Headers/riscv_packed_simd.h
@@ -478,6 +478,10 @@ __packed_mulh_builtin(mulhsu_i32, int32_t, int32_t, uint32_t)
 __packed_mulh_builtin(mulhrsu_i32, int32_t, int32_t, uint32_t)
 #undef __packed_mulh_builtin
 
+/* Scalar "Q-format" Multiplication */
+__packed_binary_builtin(mulq_i32, int32_t, __builtin_riscv_mulq_i32)
+__packed_binary_builtin(mulqr_i32, int32_t, __builtin_riscv_mulqr_i32)
+
 /* Packed Splat (32-bit) */
 __packed_splat(pmv_s_u8x4, uint8x4_t, uint8_t, __packed_splat4)
 __packed_splat(pmv_s_i8x4, int8x4_t, int8_t, __packed_splat4)

diff  --git a/clang/test/CodeGen/RISCV/rvp-intrinsics.c b/clang/test/CodeGen/RISCV/rvp-intrinsics.c
index 9866b4915d267..34aaaf4df1561 100644
--- a/clang/test/CodeGen/RISCV/rvp-intrinsics.c
+++ b/clang/test/CodeGen/RISCV/rvp-intrinsics.c
@@ -396,6 +396,40 @@ int32_t test_mulhrsu_i32(int32_t a, uint32_t b) {
   return __riscv_mulhrsu_i32(a, b);
 }
 
+/* Scalar "Q-format" Multiplication */
+
+// RV32-LABEL: define dso_local i32 @test_mulq_i32(
+// RV32-SAME: i32 noundef [[A:%.*]], i32 noundef [[B:%.*]]) #[[ATTR0]] {
+// RV32-NEXT:  [[ENTRY:.*:]]
+// RV32-NEXT:    [[TMP0:%.*]] = call i32 @llvm.riscv.mulq.i32(i32 [[A]], i32 [[B]])
+// RV32-NEXT:    ret i32 [[TMP0]]
+//
+// RV64-LABEL: define dso_local signext i32 @test_mulq_i32(
+// RV64-SAME: i32 noundef signext [[A:%.*]], i32 noundef signext [[B:%.*]]) #[[ATTR0]] {
+// RV64-NEXT:  [[ENTRY:.*:]]
+// RV64-NEXT:    [[TMP0:%.*]] = call i32 @llvm.riscv.mulq.i32(i32 [[A]], i32 [[B]])
+// RV64-NEXT:    ret i32 [[TMP0]]
+//
+int32_t test_mulq_i32(int32_t a, int32_t b) {
+  return __riscv_mulq_i32(a, b);
+}
+
+// RV32-LABEL: define dso_local i32 @test_mulqr_i32(
+// RV32-SAME: i32 noundef [[A:%.*]], i32 noundef [[B:%.*]]) #[[ATTR0]] {
+// RV32-NEXT:  [[ENTRY:.*:]]
+// RV32-NEXT:    [[TMP0:%.*]] = call i32 @llvm.riscv.mulqr.i32(i32 [[A]], i32 [[B]])
+// RV32-NEXT:    ret i32 [[TMP0]]
+//
+// RV64-LABEL: define dso_local signext i32 @test_mulqr_i32(
+// RV64-SAME: i32 noundef signext [[A:%.*]], i32 noundef signext [[B:%.*]]) #[[ATTR0]] {
+// RV64-NEXT:  [[ENTRY:.*:]]
+// RV64-NEXT:    [[TMP0:%.*]] = call i32 @llvm.riscv.mulqr.i32(i32 [[A]], i32 [[B]])
+// RV64-NEXT:    ret i32 [[TMP0]]
+//
+int32_t test_mulqr_i32(int32_t a, int32_t b) {
+  return __riscv_mulqr_i32(a, b);
+}
+
 /* Packed Splat (32-bit) */
 
 // CHECK-LABEL: define dso_local i32 @test_pmv_s_u8x4(

diff  --git a/cross-project-tests/intrinsic-header-tests/riscv_packed_simd.c b/cross-project-tests/intrinsic-header-tests/riscv_packed_simd.c
index 507ad0c83f776..88450a0243c19 100644
--- a/cross-project-tests/intrinsic-header-tests/riscv_packed_simd.c
+++ b/cross-project-tests/intrinsic-header-tests/riscv_packed_simd.c
@@ -3122,6 +3122,21 @@ int32_t test_mulhrsu_i32(int32_t rs1, uint32_t rs2) {
   return __riscv_mulhrsu_i32(rs1, rs2);
 }
 
+// Scalar "Q-format" multiplication
+// CHECK-LABEL: test_mulq_i32:
+// RV32:        mulq{{[[:space:]]}}
+// RV64:        pmulq.w
+int32_t test_mulq_i32(int32_t rs1, int32_t rs2) {
+  return __riscv_mulq_i32(rs1, rs2);
+}
+
+// CHECK-LABEL: test_mulqr_i32:
+// RV32:        mulqr{{[[:space:]]}}
+// RV64:        pmulqr.w
+int32_t test_mulqr_i32(int32_t rs1, int32_t rs2) {
+  return __riscv_mulqr_i32(rs1, rs2);
+}
+
 // CHECK-LABEL: test_pmulh_i16x2:
 // CHECK:       pmulh.h
 int16x2_t test_pmulh_i16x2(int16x2_t rs1, int16x2_t rs2) {

diff  --git a/llvm/include/llvm/IR/IntrinsicsRISCV.td b/llvm/include/llvm/IR/IntrinsicsRISCV.td
index c33f0fa792f0f..926641511ae38 100644
--- a/llvm/include/llvm/IR/IntrinsicsRISCV.td
+++ b/llvm/include/llvm/IR/IntrinsicsRISCV.td
@@ -2186,6 +2186,11 @@ class RVPBinaryIntrinsic
   def int_riscv_mulhsu_i32  : RVPScalarMulHighIntrinsic;
   def int_riscv_mulhrsu_i32 : RVPScalarMulHighIntrinsic;
 
+  // Scalar "Q-format" Multiplication. On RV64 these map to the packed
+  // pmulq.w family on the low words.
+  def int_riscv_mulq_i32  : RVPScalarBinaryIntrinsic;
+  def int_riscv_mulqr_i32 : RVPScalarBinaryIntrinsic;
+
   // Packed Multiply High Accumulate.
   def int_riscv_pmhacc    : RVPTernaryIntrinsic;
   def int_riscv_pmhracc   : RVPTernaryIntrinsic;

diff  --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 668e037415a9d..f28ac3efbabab 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -12439,6 +12439,17 @@ static unsigned getRVScalarMulHighOpcode(unsigned IntNo) {
   }
 }
 
+static unsigned getRVScalarQFormatMulOpcode(unsigned IntNo) {
+  switch (IntNo) {
+  default:
+    llvm_unreachable("Unexpected RISC-V scalar Q-format multiply intrinsic");
+  case Intrinsic::riscv_mulq_i32:
+    return RISCVISD::MULQ;
+  case Intrinsic::riscv_mulqr_i32:
+    return RISCVISD::MULQR;
+  }
+}
+
 static unsigned getRVPMulHighAccumulateOpcode(unsigned IntNo) {
   switch (IntNo) {
   default:
@@ -13370,6 +13381,13 @@ SDValue RISCVTargetLowering::LowerINTRINSIC_WO_CHAIN(SDValue Op,
     unsigned Opc = getRVScalarMulHighOpcode(IntNo);
     return DAG.getNode(Opc, DL, MVT::i32, Op.getOperand(1), Op.getOperand(2));
   }
+  case Intrinsic::riscv_mulq_i32:
+  case Intrinsic::riscv_mulqr_i32: {
+    // RV32 selects the scalar P instructions directly. RV64 goes via
+    // ReplaceNodeResults.
+    unsigned Opc = getRVScalarQFormatMulOpcode(IntNo);
+    return DAG.getNode(Opc, DL, MVT::i32, Op.getOperand(1), Op.getOperand(2));
+  }
   case Intrinsic::riscv_pmhacc:
   case Intrinsic::riscv_pmhracc:
   case Intrinsic::riscv_pmhaccu:
@@ -18057,6 +18075,22 @@ void RISCVTargetLowering::ReplaceNodeResults(SDNode *N,
       Results.push_back(DAG.getExtractVectorElt(DL, MVT::i32, Res, 0));
       return;
     }
+    case Intrinsic::riscv_mulq_i32:
+    case Intrinsic::riscv_mulqr_i32: {
+      // RV64 has no scalar Q-format multiply instructions; reuse the packed
+      // pmulq.w family on the low words, whose element 0 is the scalar result.
+      MVT VT = N->getSimpleValueType(0);
+      if (!Subtarget.is64Bit() || VT != MVT::i32)
+        return;
+      unsigned Opc = getRVScalarQFormatMulOpcode(IntNo);
+      SDValue Rs1 =
+          DAG.getNode(ISD::SCALAR_TO_VECTOR, DL, MVT::v2i32, N->getOperand(1));
+      SDValue Rs2 =
+          DAG.getNode(ISD::SCALAR_TO_VECTOR, DL, MVT::v2i32, N->getOperand(2));
+      SDValue Res = DAG.getNode(Opc, DL, MVT::v2i32, Rs1, Rs2);
+      Results.push_back(DAG.getExtractVectorElt(DL, MVT::i32, Res, 0));
+      return;
+    }
     case Intrinsic::riscv_pnclipp:
     case Intrinsic::riscv_pnclipup: {
       bool IsSigned = IntNo == Intrinsic::riscv_pnclipp;

diff  --git a/llvm/test/CodeGen/RISCV/rv32p.ll b/llvm/test/CodeGen/RISCV/rv32p.ll
index 1a4d623427a0a..9bd8e87a1e253 100644
--- a/llvm/test/CodeGen/RISCV/rv32p.ll
+++ b/llvm/test/CodeGen/RISCV/rv32p.ll
@@ -2421,3 +2421,21 @@ define i32 @test_mulhrsu_i32(i32 %rs1, i32 %rs2) {
   %res = call i32 @llvm.riscv.mulhrsu.i32(i32 %rs1, i32 %rs2)
   ret i32 %res
 }
+
+define i32 @test_mulq_i32(i32 %a, i32 %b) {
+; CHECK-LABEL: test_mulq_i32:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    mulq a0, a0, a1
+; CHECK-NEXT:    ret
+  %res = call i32 @llvm.riscv.mulq.i32(i32 %a, i32 %b)
+  ret i32 %res
+}
+
+define i32 @test_mulqr_i32(i32 %a, i32 %b) {
+; CHECK-LABEL: test_mulqr_i32:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    mulqr a0, a0, a1
+; CHECK-NEXT:    ret
+  %res = call i32 @llvm.riscv.mulqr.i32(i32 %a, i32 %b)
+  ret i32 %res
+}

diff  --git a/llvm/test/CodeGen/RISCV/rv64p.ll b/llvm/test/CodeGen/RISCV/rv64p.ll
index 5ceae2996fe3d..d94ff361cf4f1 100644
--- a/llvm/test/CodeGen/RISCV/rv64p.ll
+++ b/llvm/test/CodeGen/RISCV/rv64p.ll
@@ -1897,3 +1897,21 @@ define i32 @test_asubu_u32(i32 %a, i32 %b) {
   %res = call i32 @llvm.riscv.asubu.u32(i32 %a, i32 %b)
   ret i32 %res
 }
+
+define i32 @test_mulq_i32(i32 %a, i32 %b) {
+; CHECK-LABEL: test_mulq_i32:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    pmulq.w a0, a0, a1
+; CHECK-NEXT:    ret
+  %res = call i32 @llvm.riscv.mulq.i32(i32 %a, i32 %b)
+  ret i32 %res
+}
+
+define i32 @test_mulqr_i32(i32 %a, i32 %b) {
+; CHECK-LABEL: test_mulqr_i32:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    pmulqr.w a0, a0, a1
+; CHECK-NEXT:    ret
+  %res = call i32 @llvm.riscv.mulqr.i32(i32 %a, i32 %b)
+  ret i32 %res
+}


        


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