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D152023 <https://reviews.llvm.org/D152023> made ubsan consider __builtin_clz of
0 undefined regardless of
the target. This ensures portability and matches gcc.
This causes the ACLE intrinsics to also be considered to also be
considered to be undefined for 0 since they used the generic builtins
as their implementation.
This patch adds builtins for ARM that ubsan doesn't know about to make
the behavior defined for 0. Alternatively, I could have added a zero
check to the intrinsics, but the dedicated builtin will give better -O0
codegen.
Fixes #63113.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D154915
Files:
clang/include/clang/Basic/BuiltinsAArch64.def
clang/include/clang/Basic/BuiltinsARM.def
clang/lib/CodeGen/CGBuiltin.cpp
clang/lib/Headers/arm_acle.h
clang/test/CodeGen/arm_acle.c
Index: clang/test/CodeGen/arm_acle.c
===================================================================
--- clang/test/CodeGen/arm_acle.c
+++ clang/test/CodeGen/arm_acle.c
@@ -344,8 +344,8 @@
// AArch64-LABEL: @test_clzl(
// AArch64-NEXT: entry:
// AArch64-NEXT: [[TMP0:%.*]] = call i64 @llvm.ctlz.i64(i64 [[T:%.*]], i1 false)
-// AArch64-NEXT: [[CAST_I:%.*]] = trunc i64 [[TMP0]] to i32
-// AArch64-NEXT: [[CONV_I:%.*]] = sext i32 [[CAST_I]] to i64
+// AArch64-NEXT: [[TMP1:%.*]] = trunc i64 [[TMP0]] to i32
+// AArch64-NEXT: [[CONV_I:%.*]] = zext i32 [[TMP1]] to i64
// AArch64-NEXT: ret i64 [[CONV_I]]
//
long test_clzl(long t) {
@@ -355,8 +355,8 @@
// ARM-LABEL: @test_clzll(
// ARM-NEXT: entry:
// ARM-NEXT: [[TMP0:%.*]] = call i64 @llvm.ctlz.i64(i64 [[T:%.*]], i1 false)
-// ARM-NEXT: [[CAST_I:%.*]] = trunc i64 [[TMP0]] to i32
-// ARM-NEXT: [[CONV_I:%.*]] = sext i32 [[CAST_I]] to i64
+// ARM-NEXT: [[TMP1:%.*]] = trunc i64 [[TMP0]] to i32
+// ARM-NEXT: [[CONV_I:%.*]] = zext i32 [[TMP1]] to i64
// ARM-NEXT: ret i64 [[CONV_I]]
//
uint64_t test_clzll(uint64_t t) {
Index: clang/lib/Headers/arm_acle.h
===================================================================
--- clang/lib/Headers/arm_acle.h
+++ clang/lib/Headers/arm_acle.h
@@ -140,17 +140,21 @@
/* CLZ */
static __inline__ uint32_t __attribute__((__always_inline__, __nodebug__))
__clz(uint32_t __t) {
- return (uint32_t)__builtin_clz(__t);
+ return __builtin_arm_clz(__t);
}
static __inline__ unsigned long __attribute__((__always_inline__, __nodebug__))
__clzl(unsigned long __t) {
- return (unsigned long)__builtin_clzl(__t);
+#if __SIZEOF_LONG__ == 4
+ return __builtin_arm_clz(__t);
+#else
+ return __builtin_arm_clz64(__t);
+#endif
}
static __inline__ uint64_t __attribute__((__always_inline__, __nodebug__))
__clzll(uint64_t __t) {
- return (uint64_t)__builtin_clzll(__t);
+ return __builtin_arm_clz64(__t);
}
/* CLS */
Index: clang/lib/CodeGen/CGBuiltin.cpp
===================================================================
--- clang/lib/CodeGen/CGBuiltin.cpp
+++ clang/lib/CodeGen/CGBuiltin.cpp
@@ -7948,6 +7948,17 @@
CGM.getIntrinsic(Intrinsic::bitreverse, Arg->getType()), Arg, "rbit");
}
+ if (BuiltinID == clang::ARM::BI__builtin_arm_clz ||
+ BuiltinID == clang::ARM::BI__builtin_arm_clz64) {
+ llvm::Value *Arg = EmitScalarExpr(E->getArg(0));
+ Function *F = CGM.getIntrinsic(Intrinsic::ctlz, Arg->getType());
+ Value *Res = Builder.CreateCall(F, {Arg, Builder.getInt1(false)});
+ if (BuiltinID == clang::ARM::BI__builtin_arm_clz64)
+ Res = Builder.CreateTrunc(Res, Builder.getInt32Ty());
+ return Res;
+ }
+
+
if (BuiltinID == clang::ARM::BI__builtin_arm_cls) {
llvm::Value *Arg = EmitScalarExpr(E->getArg(0));
return Builder.CreateCall(CGM.getIntrinsic(Intrinsic::arm_cls), Arg, "cls");
@@ -10030,6 +10041,16 @@
CGM.getIntrinsic(Intrinsic::bitreverse, Arg->getType()), Arg, "rbit");
}
+ if (BuiltinID == clang::AArch64::BI__builtin_arm_clz ||
+ BuiltinID == clang::AArch64::BI__builtin_arm_clz64) {
+ llvm::Value *Arg = EmitScalarExpr(E->getArg(0));
+ Function *F = CGM.getIntrinsic(Intrinsic::ctlz, Arg->getType());
+ Value *Res = Builder.CreateCall(F, {Arg, Builder.getInt1(false)});
+ if (BuiltinID == clang::AArch64::BI__builtin_arm_clz64)
+ Res = Builder.CreateTrunc(Res, Builder.getInt32Ty());
+ return Res;
+ }
+
if (BuiltinID == clang::AArch64::BI__builtin_arm_cls) {
llvm::Value *Arg = EmitScalarExpr(E->getArg(0));
return Builder.CreateCall(CGM.getIntrinsic(Intrinsic::aarch64_cls), Arg,
Index: clang/include/clang/Basic/BuiltinsARM.def
===================================================================
--- clang/include/clang/Basic/BuiltinsARM.def
+++ clang/include/clang/Basic/BuiltinsARM.def
@@ -119,6 +119,8 @@
// Bit manipulation
BUILTIN(__builtin_arm_rbit, "UiUi", "nc")
+BUILTIN(__builtin_arm_clz, "UiZUi", "nc")
+BUILTIN(__builtin_arm_clz64, "UiWUi", "nc")
BUILTIN(__builtin_arm_cls, "UiZUi", "nc")
BUILTIN(__builtin_arm_cls64, "UiWUi", "nc")
Index: clang/include/clang/Basic/BuiltinsAArch64.def
===================================================================
--- clang/include/clang/Basic/BuiltinsAArch64.def
+++ clang/include/clang/Basic/BuiltinsAArch64.def
@@ -39,6 +39,8 @@
BUILTIN(__builtin_arm_rbit64, "WUiWUi", "nc")
BUILTIN(__builtin_arm_cls, "UiZUi", "nc")
BUILTIN(__builtin_arm_cls64, "UiWUi", "nc")
+BUILTIN(__builtin_arm_clz, "UiZUi", "nc")
+BUILTIN(__builtin_arm_clz64, "UiWUi", "nc")
// HINT
BUILTIN(__builtin_arm_nop, "v", "")
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