[clang] [Clang][RISCV] Add missing support for `__builtin_riscv_cpop_32/64` (PR #76256)

[Yingwei Zheng via cfe-commits]

https://github.com/dtcxzyw created https://github.com/llvm/llvm-project/pull/76256

This patch adds support for `__builtin_riscv_cpop_32/64`, which are used by `riscv_bitmanip.h`.
See also https://github.com/llvm/llvm-project/blob/04c473bea3e0f135432698fcaafab52e1fe1b5ec/clang/lib/Headers/riscv_bitmanip.h#L35-L60.
Thank @Liaoshihua for reporting this!


>From a69599fcda5f1a4df13ec0bfe3432ba39ef09246 Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2333 at gmail.com>
Date: Sat, 23 Dec 2023 01:21:39 +0800
Subject: [PATCH] [Clang][RISCV] Add missing support for
 __builtin_riscv_cpop_32/64

---
 clang/include/clang/Basic/BuiltinsRISCV.def   |  2 ++
 clang/lib/CodeGen/CGBuiltin.cpp               | 10 +++++++
 clang/test/CodeGen/RISCV/rvb-intrinsics/zbb.c | 26 +++++++++++++++++++
 3 files changed, 38 insertions(+)

diff --git a/clang/include/clang/Basic/BuiltinsRISCV.def b/clang/include/clang/Basic/BuiltinsRISCV.def
index 1528b18c82eade..1df1c53733cfa1 100644
--- a/clang/include/clang/Basic/BuiltinsRISCV.def
+++ b/clang/include/clang/Basic/BuiltinsRISCV.def
@@ -22,6 +22,8 @@ TARGET_BUILTIN(__builtin_riscv_clz_32, "UiUi", "nc", "zbb|xtheadbb")
 TARGET_BUILTIN(__builtin_riscv_clz_64, "UiUWi", "nc", "zbb|xtheadbb,64bit")
 TARGET_BUILTIN(__builtin_riscv_ctz_32, "UiUi", "nc", "zbb")
 TARGET_BUILTIN(__builtin_riscv_ctz_64, "UiUWi", "nc", "zbb,64bit")
+TARGET_BUILTIN(__builtin_riscv_cpop_32, "UiUi", "nc", "zbb")
+TARGET_BUILTIN(__builtin_riscv_cpop_64, "UiUWi", "nc", "zbb,64bit")
 
 // Zbc or Zbkc extension
 TARGET_BUILTIN(__builtin_riscv_clmul_32, "UiUiUi", "nc", "zbc|zbkc")
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 5081062da2862e..64210e76ed2218 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -20696,6 +20696,8 @@ Value *CodeGenFunction::EmitRISCVBuiltinExpr(unsigned BuiltinID,
   case RISCV::BI__builtin_riscv_clz_64:
   case RISCV::BI__builtin_riscv_ctz_32:
   case RISCV::BI__builtin_riscv_ctz_64:
+  case RISCV::BI__builtin_riscv_cpop_32:
+  case RISCV::BI__builtin_riscv_cpop_64:
   case RISCV::BI__builtin_riscv_clmul_32:
   case RISCV::BI__builtin_riscv_clmul_64:
   case RISCV::BI__builtin_riscv_clmulh_32:
@@ -20735,6 +20737,14 @@ Value *CodeGenFunction::EmitRISCVBuiltinExpr(unsigned BuiltinID,
                                        "cast");
       return Result;
     }
+    case RISCV::BI__builtin_riscv_cpop_32:
+    case RISCV::BI__builtin_riscv_cpop_64: {
+      Value *Result = Builder.CreateUnaryIntrinsic(Intrinsic::ctpop, Ops[0]);
+      if (Result->getType() != ResultType)
+        Result = Builder.CreateIntCast(Result, ResultType, /*isSigned*/ true,
+                                       "cast");
+      return Result;
+    }
 
     // Zbc
     case RISCV::BI__builtin_riscv_clmul_32:
diff --git a/clang/test/CodeGen/RISCV/rvb-intrinsics/zbb.c b/clang/test/CodeGen/RISCV/rvb-intrinsics/zbb.c
index 3a421f8c6cd421..a5715e330172bd 100644
--- a/clang/test/CodeGen/RISCV/rvb-intrinsics/zbb.c
+++ b/clang/test/CodeGen/RISCV/rvb-intrinsics/zbb.c
@@ -82,3 +82,29 @@ unsigned int ctz_64(unsigned long a) {
   return __builtin_riscv_ctz_64(a);
 }
 #endif
+
+// RV32ZBB-LABEL: @cpop_32(
+// RV32ZBB-NEXT:  entry:
+// RV32ZBB-NEXT:    [[TMP0:%.*]] = call i32 @llvm.ctpop.i32(i32 [[A:%.*]])
+// RV32ZBB-NEXT:    ret i32 [[TMP0]]
+//
+// RV64ZBB-LABEL: @cpop_32(
+// RV64ZBB-NEXT:  entry:
+// RV64ZBB-NEXT:    [[TMP0:%.*]] = call i32 @llvm.ctpop.i32(i32 [[A:%.*]])
+// RV64ZBB-NEXT:    ret i32 [[TMP0]]
+//
+unsigned int cpop_32(unsigned int a) {
+  return __builtin_riscv_cpop_32(a);
+}
+
+#if __riscv_xlen == 64
+// RV64ZBB-LABEL: @cpop_64(
+// RV64ZBB-NEXT:  entry:
+// RV64ZBB-NEXT:    [[TMP0:%.*]] = call i64 @llvm.ctpop.i64(i64 [[A:%.*]])
+// RV64ZBB-NEXT:    [[CAST:%.*]] = trunc i64 [[TMP0]] to i32
+// RV64ZBB-NEXT:    ret i32 [[CAST]]
+//
+unsigned int cpop_64(unsigned long a) {
+  return __builtin_riscv_cpop_64(a);
+}
+#endif