[RISCV] Add clang builtins for CLZ instruction.

[joker881]

Summary

add intrinsic for CLZ

[craig.topper]

These were intentionally not added because llvm has generic leading and trailing zero builtins. builtin_clz and builtin_ctz

[craig.topper]

Rethinking that. Since builtin_clz is undefined for 0, I think we should have clang builtins, but we should use llvm.ctlz with false for the second argument as their implementation. See X86::BIbuiltin_ia32_lzcnt_u32 for example.

[joker881]

[RISCV]CLZ instruction try use llvm.ctlz with false for the second argument to implement clz

[craig.topper]

clang/lib/CodeGen/CGBuiltin.cpp

18910

Add a space before the opening curly brace

18913

Fix the clang-format warning here

clang/test/CodeGen/RISCV/rvb-intrinsics/riscv32-zbb.c

21

There is no llvm.riscv.clz.i32 intrinsic. Was this test not updated?

[joker881]

upadated test files, fixed the format problem

[joker881]

wait ,It seems the format problem have not solved,sorry

[joker881]

upadated test files, fixed the format problem

[joker881]

upadated test files, fixed the format problem

[craig.topper]

LGTM though I think the title needs to be updated. Should be something like "[RISCV] Add clang builtins for CLZ instruction."

clang/include/clang/Basic/BuiltinsRISCV.def

 
 #if defined(BUILTIN) && !defined(TARGET_BUILTIN)
 #   define TARGET_BUILTIN(ID, TYPE, ATTRS, FEATURE) BUILTIN(ID, TYPE, ATTRS)
 #endif
 
 // Zbb extension
 TARGET_BUILTIN(__builtin_riscv_orc_b_32, "ZiZi", "nc", "zbb")
 TARGET_BUILTIN(__builtin_riscv_orc_b_64, "WiWi", "nc", "zbb,64bit")
-
+TARGET_BUILTIN(__builtin_riscv_clz_32, "ZiZi", "nc", "zbb")
+TARGET_BUILTIN(__builtin_riscv_clz_64, "WiWi", "nc", "zbb,64bit")
 // Zbc or Zbkc extension
 TARGET_BUILTIN(__builtin_riscv_clmul, "LiLiLi", "nc", "zbc|zbkc")
 TARGET_BUILTIN(__builtin_riscv_clmulh, "LiLiLi", "nc", "zbc|zbkc")
 TARGET_BUILTIN(__builtin_riscv_clmulr, "LiLiLi", "nc", "zbc")
 
 // Zbkx
 TARGET_BUILTIN(__builtin_riscv_xperm4, "LiLiLi", "nc", "zbkx")
 TARGET_BUILTIN(__builtin_riscv_xperm8, "LiLiLi", "nc", "zbkx")

clang/lib/CodeGen/CGBuiltin.cpp

 //===---- CGBuiltin.cpp - Emit LLVM Code for builtins ---------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
Value *CodeGenFunction::EmitRISCVBuiltinExpr(unsigned BuiltinID,
   case RISCV::BI__builtin_riscv_unzip_32: {
     switch (BuiltinID) {
     default: llvm_unreachable("unexpected builtin ID");
     // Zbb
     case RISCV::BI__builtin_riscv_orc_b_32:
     case RISCV::BI__builtin_riscv_orc_b_64:
       ID = Intrinsic::riscv_orc_b;
       break;
-
+    case RISCV::BI__builtin_riscv_clz_32:
+    case RISCV::BI__builtin_riscv_clz_64:{
+      Function *F = CGM.getIntrinsic(Intrinsic::ctlz, Ops[0]->getType());
+      return Builder.CreateCall(F, {Ops[0], Builder.getInt1(false)});
+  }
     // Zbc
     case RISCV::BI__builtin_riscv_clmul:
       ID = Intrinsic::riscv_clmul;
       break;
     case RISCV::BI__builtin_riscv_clmulh:
       ID = Intrinsic::riscv_clmulh;
       break;
     case RISCV::BI__builtin_riscv_clmulr:

clang/test/CodeGen/RISCV/rvb-intrinsics/riscv32-zbb.c

 // NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py
 // RUN: %clang_cc1 -triple riscv32 -target-feature +zbb -emit-llvm %s -o - \
 // RUN:     | FileCheck %s  -check-prefix=RV32ZBB
 
 // RV32ZBB-LABEL: @orc_b_32(
 // RV32ZBB-NEXT:  entry:
 // RV32ZBB-NEXT:    [[A_ADDR:%.*]] = alloca i32, align 4
 // RV32ZBB-NEXT:    store i32 [[A:%.*]], i32* [[A_ADDR]], align 4
 // RV32ZBB-NEXT:    [[TMP0:%.*]] = load i32, i32* [[A_ADDR]], align 4
 // RV32ZBB-NEXT:    [[TMP1:%.*]] = call i32 @llvm.riscv.orc.b.i32(i32 [[TMP0]])
 // RV32ZBB-NEXT:    ret i32 [[TMP1]]
 //
 int orc_b_32(int a) {
   return __builtin_riscv_orc_b_32(a);
 }
+// RV32ZBB-LABEL: @clz_32(
+// RV32ZBB-NEXT:  entry:
+// RV32ZBB-NEXT:    [[A_ADDR:%.*]] = alloca i32, align 4
+// RV32ZBB-NEXT:    store i32 [[A:%.*]], i32* [[A_ADDR]], align 4
+// RV32ZBB-NEXT:    [[TMP0:%.*]] = load i32, i32* [[A_ADDR]], align 4
+// RV32ZBB-NEXT:    [[TMP1:%.*]] = call i32 @llvm.riscv.clz.i32(i32 [[TMP0]])
+// RV32ZBB-NEXT:    ret i32 [[TMP1]]
+//
+int clz_32(int a) {
+  return __builtin_riscv_clz_32(a);
+}

clang/test/CodeGen/RISCV/rvb-intrinsics/riscv64-zbb.c

 // RV64ZBB-NEXT:    store i64 [[A:%.*]], i64* [[A_ADDR]], align 8
 // RV64ZBB-NEXT:    [[TMP0:%.*]] = load i64, i64* [[A_ADDR]], align 8
 // RV64ZBB-NEXT:    [[TMP1:%.*]] = call i64 @llvm.riscv.orc.b.i64(i64 [[TMP0]])
 // RV64ZBB-NEXT:    ret i64 [[TMP1]]
 //
 long orc_b_64(long a) {
   return __builtin_riscv_orc_b_64(a);
 }
+
+
+// RV64ZBB-LABEL: @clz_32(
+// RV64ZBB-NEXT:  entry:
+// RV64ZBB-NEXT:    [[A_ADDR:%.*]] = alloca i32, align 4
+// RV64ZBB-NEXT:    store i32 [[A:%.*]], i32* [[A_ADDR]], align 4
+// RV64ZBB-NEXT:    [[TMP0:%.*]] = load i32, i32* [[A_ADDR]], align 4
+// RV64ZBB-NEXT:    [[TMP1:%.*]] = call i32 @llvm.riscv.clz.i32(i32 [[TMP0]])
+// RV64ZBB-NEXT:    ret i32 [[TMP1]]
+//
+int clz_32(int a) {
+  return __builtin_riscv_clz_32(a);
+}
+
+// RV64ZBB-LABEL: @clz_64(
+// RV64ZBB-NEXT:  entry:
+// RV64ZBB-NEXT:    [[A_ADDR:%.*]] = alloca i64, align 8
+// RV64ZBB-NEXT:    store i64 [[A:%.*]], i64* [[A_ADDR]], align 8
+// RV64ZBB-NEXT:    [[TMP0:%.*]] = load i64, i64* [[A_ADDR]], align 8
+// RV64ZBB-NEXT:    [[TMP1:%.*]] = call i64 @llvm.riscv.clz.i64(i64 [[TMP0]])
+// RV64ZBB-NEXT:    ret i64 [[TMP1]]
+//
+long clz_64(long a) {
+  return __builtin_riscv_clz_64(a);
+}