[ARM][AArch64] Implement __cls, __clsl and __clsll intrinsics from ACLE
Summary:
Writing support for three ACLE functions:
unsigned int __cls(uint32_t x)
unsigned int __clsl(unsigned long x)
unsigned int __clsll(uint64_t x)
CLS stands for "Count number of leading sign bits".
In AArch64, these two intrinsics can be translated into the 'cls'
instruction directly. In AArch32, on the other hand, this functionality
is achieved by implementing it in terms of clz (count number of leading
zeros).
Reviewers: compnerd
Reviewed By: compnerd
Subscribers: kristof.beyls, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D69250
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 9a56116..648837a 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -6055,6 +6055,16 @@
CGM.getIntrinsic(Intrinsic::bitreverse, Arg->getType()), Arg, "rbit");
}
+ if (BuiltinID == ARM::BI__builtin_arm_cls) {
+ llvm::Value *Arg = EmitScalarExpr(E->getArg(0));
+ return Builder.CreateCall(CGM.getIntrinsic(Intrinsic::arm_cls), Arg, "cls");
+ }
+ if (BuiltinID == ARM::BI__builtin_arm_cls64) {
+ llvm::Value *Arg = EmitScalarExpr(E->getArg(0));
+ return Builder.CreateCall(CGM.getIntrinsic(Intrinsic::arm_cls64), Arg,
+ "cls");
+ }
+
if (BuiltinID == ARM::BI__clear_cache) {
assert(E->getNumArgs() == 2 && "__clear_cache takes 2 arguments");
const FunctionDecl *FD = E->getDirectCallee();
@@ -7108,6 +7118,17 @@
CGM.getIntrinsic(Intrinsic::bitreverse, Arg->getType()), Arg, "rbit");
}
+ if (BuiltinID == AArch64::BI__builtin_arm_cls) {
+ llvm::Value *Arg = EmitScalarExpr(E->getArg(0));
+ return Builder.CreateCall(CGM.getIntrinsic(Intrinsic::aarch64_cls), Arg,
+ "cls");
+ }
+ if (BuiltinID == AArch64::BI__builtin_arm_cls64) {
+ llvm::Value *Arg = EmitScalarExpr(E->getArg(0));
+ return Builder.CreateCall(CGM.getIntrinsic(Intrinsic::aarch64_cls64), Arg,
+ "cls");
+ }
+
if (BuiltinID == AArch64::BI__builtin_arm_jcvt) {
assert((getContext().getTypeSize(E->getType()) == 32) &&
"__jcvt of unusual size!");