Tom Stellard 3203143f13 CodeGen: Improve generated IR for __builtin_mul_overflow(uint, uint, int) ...

Add a special case for handling __builtin_mul_overflow with unsigned
inputs and a signed output to avoid emitting the __muloti4 library
call on x86_64.  __muloti4 is not implemented in libgcc, so avoiding
this call fixes compilation of some programs that call
__builtin_mul_overflow with these arguments.

For example, this fixes the build of cpio with clang, which includes code from
gnulib that calls __builtin_mul_overflow with these argument types.

Reviewed By: vsk

Differential Revision: https://reviews.llvm.org/D84405

2020-12-17 14:30:31 -08:00

23 KiB

Raw Blame History

View Raw