llvm - http://llvm.org

Age	Commit message (Collapse)	Author
2013-03-27	Don't spill PPC VRSAVE on non-Darwin (even in SjLj)	Hal Finkel
	As Bill Schmidt pointed out to me, only on Darwin do we need to spill/restore VRSAVE in the SjLj code. For non-Darwin, don't spill/restore VRSAVE (and I've added some asserts to make sure that we're not). As it turns out, we're not currently handling the Darwin case correctly (I've added a FIXME in the test case). I've tried adding various implied register definitions/uses to force the spill without success, so I'll need to address this later. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178096 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-21	Implement builtin_{setjmp/longjmp} on PPC	Hal Finkel
	This implements SJLJ lowering on PPC, making the Clang functions __builtin_{setjmp/longjmp} functional on PPC platforms. The implementation strategy is similar to that on X86, with the exception that a branch-and-link variant is used to get the right jump address. Credit goes to Bill Schmidt for suggesting the use of the unconditional bcl form (instead of the regular bl instruction) to limit return-address-cache pollution. Benchmarking the speed at -O3 of: static jmp_buf env_sigill; void foo() { __builtin_longjmp(env_sigill,1); } main() { ... for (int i = 0; i < c; ++i) { if (__builtin_setjmp(env_sigill)) { goto done; } else { foo(); } done:; } ... } vs. the same code using the libc setjmp/longjmp functions on a P7 shows that this builtin implementation is ~4x faster with Altivec enabled and ~7.25x faster with Altivec disabled. This comparison is somewhat unfair because the libc version must also save/restore the VSX registers which we don't yet support. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177666 91177308-0d34-0410-b5e6-96231b3b80d8