[llvm] 1131e44 - [RISCV] Use hasCPOPLike in isCtpopFast and getPopcntSupport (#158371)

[via llvm-commits]

Author: Craig Topper
Date: 2025-09-12T15:29:44-07:00
New Revision: 1131e44ed3f5fadb2d22ff155d4e47f69757d02f

URL: https://github.com/llvm/llvm-project/commit/1131e44ed3f5fadb2d22ff155d4e47f69757d02f
DIFF: https://github.com/llvm/llvm-project/commit/1131e44ed3f5fadb2d22ff155d4e47f69757d02f.diff

LOG: [RISCV] Use hasCPOPLike in isCtpopFast and getPopcntSupport (#158371)

Added: 
    

Modified: 
    llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
    llvm/test/CodeGen/RISCV/xcvbitmanip.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index c3071ad5cd697..f9b484b98739f 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -24844,8 +24844,7 @@ bool RISCVTargetLowering::isCtpopFast(EVT VT) const {
     return isTypeLegal(VT) && Subtarget.hasStdExtZvbb();
   if (VT.isFixedLengthVector() && Subtarget.hasStdExtZvbb())
     return true;
-  // FIXME: Should use hasCPOPLike here.
-  return Subtarget.hasStdExtZbb() &&
+  return Subtarget.hasCPOPLike() &&
          (VT == MVT::i32 || VT == MVT::i64 || VT.isFixedLengthVector());
 }
 

diff  --git a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
index 1ca513214f67c..a06faa414a2ef 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
@@ -289,9 +289,7 @@ bool RISCVTTIImpl::hasActiveVectorLength() const {
 TargetTransformInfo::PopcntSupportKind
 RISCVTTIImpl::getPopcntSupport(unsigned TyWidth) const {
   assert(isPowerOf2_32(TyWidth) && "Ty width must be power of 2");
-  return ST->hasStdExtZbb() || (ST->hasVendorXCVbitmanip() && !ST->is64Bit())
-             ? TTI::PSK_FastHardware
-             : TTI::PSK_Software;
+  return ST->hasCPOPLike() ? TTI::PSK_FastHardware : TTI::PSK_Software;
 }
 
 InstructionCost RISCVTTIImpl::getPartialReductionCost(

diff  --git a/llvm/test/CodeGen/RISCV/xcvbitmanip.ll b/llvm/test/CodeGen/RISCV/xcvbitmanip.ll
index d25ff28475c4b..b2cebabb7df8b 100644
--- a/llvm/test/CodeGen/RISCV/xcvbitmanip.ll
+++ b/llvm/test/CodeGen/RISCV/xcvbitmanip.ll
@@ -229,3 +229,50 @@ define i32 @test.llvm.bitrev(i32 %a) {
   %1 = call i32 @llvm.bitreverse(i32 %a)
   ret i32 %1
 }
+
+define i1 @ctpop_i32_ult_two(i32 signext %a) nounwind {
+; CHECK-LABEL: ctpop_i32_ult_two:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    cv.cnt a0, a0
+; CHECK-NEXT:    sltiu a0, a0, 2
+; CHECK-NEXT:    ret
+  %1 = call i32 @llvm.ctpop.i32(i32 %a)
+  %2 = icmp ult i32 %1, 2
+  ret i1 %2
+}
+
+define i1 @ctpop_i32_ugt_one(i32 signext %a) nounwind {
+; CHECK-LABEL: ctpop_i32_ugt_one:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    cv.cnt a0, a0
+; CHECK-NEXT:    sltiu a0, a0, 2
+; CHECK-NEXT:    xori a0, a0, 1
+; CHECK-NEXT:    ret
+  %1 = call i32 @llvm.ctpop.i32(i32 %a)
+  %2 = icmp ugt i32 %1, 1
+  ret i1 %2
+}
+
+define i1 @ctpop_i32_eq_one(i32 signext %a) nounwind {
+; CHECK-LABEL: ctpop_i32_eq_one:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    cv.cnt a0, a0
+; CHECK-NEXT:    addi a0, a0, -1
+; CHECK-NEXT:    seqz a0, a0
+; CHECK-NEXT:    ret
+  %1 = call i32 @llvm.ctpop.i32(i32 %a)
+  %2 = icmp eq i32 %1, 1
+  ret i1 %2
+}
+
+define i1 @ctpop_i32_ne_one(i32 signext %a) nounwind {
+; CHECK-LABEL: ctpop_i32_ne_one:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    cv.cnt a0, a0
+; CHECK-NEXT:    addi a0, a0, -1
+; CHECK-NEXT:    snez a0, a0
+; CHECK-NEXT:    ret
+  %1 = call i32 @llvm.ctpop.i32(i32 %a)
+  %2 = icmp ne i32 %1, 1
+  ret i1 %2
+}