Commit Graph

2 Commits

Author SHA1 Message Date
Nick Desaulniers 6860b136b9 [MipsISelLowering] avoid emitting libcalls to __multi3
Similar to D108842 and D108844.

__has_builtin(builtin_mul_overflow) returns true for 32b MIPS targets,
but Clang is deferring to compiler RT when encountering long long types.
This breaks MIPS malta_defconfig builds of the Linux kernel that are
using __builtin_mul_overflow with these types for these targets.

If the semantics of __has_builtin mean "the compiler resolves these,
always" then we shouldn't conditionally emit a libcall.

This will still need to be worked around in the Linux kernel in order to
continue to support malta_defconfig builds of the Linux kernel for this
target with older releases of clang.

Link: https://bugs.llvm.org/show_bug.cgi?id=28629
Link: https://github.com/ClangBuiltLinux/linux/issues/1438

Reviewed By: rengolin

Differential Revision: https://reviews.llvm.org/D108926
2021-09-02 10:41:37 -07:00
Nick Desaulniers c8c176d999 [MipsISelLowering] avoid emitting libcalls to __mulodi4()
__has_builtin(__builtin_mul_overflow) returns true for 32b MIPS targets,
but Clang is deferring to compiler RT when encountering `long long`
types. This breaks sanitizer builds of the Linux kernel that are using
__builtin_mul_overflow with these types for these targets.

If the semantics of __has_builtin mean "the compiler resolves these,
always" then we shouldn't conditionally emit a libcall.

This will still need to be worked around in the Linux kernel in order to
continue to support malta_defconfig builds of the Linux kernel for this
target with older releases of clang.

Link: https://bugs.llvm.org/show_bug.cgi?id=28629
Link: https://github.com/ClangBuiltLinux/linux/issues/1438

Reviewed By: rengolin

Differential Revision: https://reviews.llvm.org/D108844
2021-08-27 15:15:36 -07:00