On Thu, 27 Aug 2020 22:34:23 -0400 George Koehler <[email protected]> wrote:
> babl and mednafen are passing -fno-unsafe-math-optimizations to clang; > this flag implies -ftrapping-math, which seems to be broken in the > PowerPC backend. Another name for -ftrapping-math is > -ffp-exception-behavior=strict I want to correct the record: -ftrapping-math is not exactly the same as -ffp-exception-behavior=strict. When you pass -fno-unsafe-math-optimizations to clang, it passes -ffp-exception-behavior=strict to the internal cc1. The strict flag enables at least -ftrapping-math and -frounding-math. The problem with mednafen on powerpc64 is in -frounding-math, not -ftrapping-math. I confirm that deleting -fno-unsafe-math-optimizations fixes the builds of babl and mednafen on macppc. I am waiting for my macppc to build clang with a backport of llvm 11's https://github.com/llvm/llvm-project/commit/d4ce862
