As described in
* https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-pure-function-attribute
* https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-const-function-attribute
An `__attribute__((pure))` function must always return, as well as an `__attribute__((const))` function.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D96960
(cherry picked from commit
46757ccb49ab88da54ca8ddd43665d5255ee80f7)
if (TargetDecl->hasAttr<ConstAttr>()) {
FuncAttrs.addAttribute(llvm::Attribute::ReadNone);
FuncAttrs.addAttribute(llvm::Attribute::NoUnwind);
+ // gcc specifies that 'const' functions have greater restrictions than
+ // 'pure' functions, so they also cannot have infinite loops.
+ FuncAttrs.addAttribute(llvm::Attribute::WillReturn);
} else if (TargetDecl->hasAttr<PureAttr>()) {
FuncAttrs.addAttribute(llvm::Attribute::ReadOnly);
FuncAttrs.addAttribute(llvm::Attribute::NoUnwind);
+ // gcc specifies that 'pure' functions cannot have infinite loops.
+ FuncAttrs.addAttribute(llvm::Attribute::WillReturn);
} else if (TargetDecl->hasAttr<NoAliasAttr>()) {
FuncAttrs.addAttribute(llvm::Attribute::ArgMemOnly);
FuncAttrs.addAttribute(llvm::Attribute::NoUnwind);
// NO__ERRNO: declare { x86_fp80, x86_fp80 } @cprojl({ x86_fp80, x86_fp80 }* byval({ x86_fp80, x86_fp80 }) align 16) [[NOT_READNONE]]
// HAS_ERRNO: declare { double, double } @cproj(double, double) [[READNONE:#[0-9]+]]
// HAS_ERRNO: declare <2 x float> @cprojf(<2 x float>) [[READNONE]]
-// HAS_ERRNO: declare { x86_fp80, x86_fp80 } @cprojl({ x86_fp80, x86_fp80 }* byval({ x86_fp80, x86_fp80 }) align 16) [[NOT_READNONE]]
+// HAS_ERRNO: declare { x86_fp80, x86_fp80 } @cprojl({ x86_fp80, x86_fp80 }* byval({ x86_fp80, x86_fp80 }) align 16) [[WILLRETURN_NOT_READNONE:#[0-9]+]]
__builtin_cpow(f,f); __builtin_cpowf(f,f); __builtin_cpowl(f,f);
// HAS_ERRNO: attributes [[NOT_READNONE]] = { nounwind {{.*}} }
// HAS_ERRNO: attributes [[READNONE]] = { {{.*}}readnone{{.*}} }
+// HAS_ERRNO: attributes [[WILLRETURN_NOT_READNONE]] = { nounwind willreturn {{.*}} }
// NO__ERRNO: declare { x86_fp80, x86_fp80 } @cprojl({ x86_fp80, x86_fp80 }* byval({ x86_fp80, x86_fp80 }) align 16) [[NOT_READNONE]]
// HAS_ERRNO: declare { double, double } @cproj(double, double) [[READNONE:#[0-9]+]]
// HAS_ERRNO: declare <2 x float> @cprojf(<2 x float>) [[READNONE]]
-// HAS_ERRNO: declare { x86_fp80, x86_fp80 } @cprojl({ x86_fp80, x86_fp80 }* byval({ x86_fp80, x86_fp80 }) align 16) [[NOT_READNONE]]
+// HAS_ERRNO: declare { x86_fp80, x86_fp80 } @cprojl({ x86_fp80, x86_fp80 }* byval({ x86_fp80, x86_fp80 }) align 16) [[WILLRETURN_NOT_READNONE:#[0-9]+]]
cpow(f,f); cpowf(f,f); cpowl(f,f);
// HAS_ERRNO: attributes [[NOT_READNONE]] = { nounwind {{.*}} }
// HAS_ERRNO: attributes [[READNONE]] = { {{.*}}readnone{{.*}} }
+// HAS_ERRNO: attributes [[WILLRETURN_NOT_READNONE]] = { nounwind willreturn {{.*}} }
// CHECK: attributes [[SR]] = { nounwind optsize{{.*}} "stackrealign"{{.*}} }
// CHECK: attributes [[RT]] = { nounwind optsize returns_twice{{.*}} }
// CHECK: attributes [[NR]] = { noreturn optsize }
-// CHECK: attributes [[NUW_RN]] = { nounwind optsize readnone }
+// CHECK: attributes [[NUW_RN]] = { nounwind optsize readnone willreturn }
// CHECK: attributes [[RT_CALL]] = { optsize returns_twice }
// CHECK: declare i32 @_Z1tv() [[TF2:#[0-9]+]]
// CHECK: attributes [[TF]] = { {{.*}} }
-// CHECK: attributes [[NUW_RN]] = { nounwind readnone{{.*}} }
-// CHECK: attributes [[NUW_RO]] = { nounwind readonly{{.*}} }
+// CHECK: attributes [[NUW_RN]] = { nounwind readnone willreturn{{.*}} }
+// CHECK: attributes [[NUW_RO]] = { nounwind readonly willreturn{{.*}} }
// CHECK: attributes [[TF2]] = { {{.*}} }
-// CHECK: attributes [[NUW_RN_CALL]] = { nounwind readnone }
-// CHECK: attributes [[NUW_RO_CALL]] = { nounwind readonly }
+// CHECK: attributes [[NUW_RN_CALL]] = { nounwind readnone willreturn }
+// CHECK: attributes [[NUW_RO_CALL]] = { nounwind readonly willreturn }
// CHECK: declare signext i32 @toupper(i32 signext) [[NUW_RO:#[0-9]+]]
// CHECK: attributes [[NUW_RO]] = { nounwind readonly{{.*}} }
-// CHECK: attributes [[NUW_RO_CALL]] = { nounwind readonly }
+// CHECK: attributes [[NUW_RO_CALL]] = { nounwind readonly willreturn }
// CHECK: declare i32 @toupper(i32) [[NUW_RO:#[0-9]+]]
// CHECK: attributes [[NUW_RO]] = { nounwind readonly{{.*}} }
-// CHECK: attributes [[NUW_RO_CALL]] = { nounwind readonly }
+// CHECK: attributes [[NUW_RO_CALL]] = { nounwind readonly willreturn }