diff options
| -rw-r--r-- | src/gallium/auxiliary/gallivm/lp_bld_logic.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_logic.c b/src/gallium/auxiliary/gallivm/lp_bld_logic.c index cdb7e0ad544..168bc262921 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_logic.c +++ b/src/gallium/auxiliary/gallivm/lp_bld_logic.c @@ -458,10 +458,22 @@ lp_build_select(struct lp_build_context *bld, mask = LLVMBuildTrunc(builder, mask, LLVMInt1TypeInContext(lc), ""); res = LLVMBuildSelect(builder, mask, a, b, ""); } - else if (HAVE_LLVM >= 0x301) { + else if (0) { /* Generate a vector select. * - * Only supported on LLVM 3.1 onwards + * XXX: Using vector selects would avoid emitting intrinsics, but they aren't + * properly supported yet. + * + * LLVM 3.1 supports it, but it yields buggy code (e.g. lp_blend_test). + * + * LLVM 3.0 includes experimental support provided the -promote-elements + * options is passed to LLVM's command line (e.g., via + * llvm::cl::ParseCommandLineOptions), but resulting code quality is much + * worse, probably because some optimization passes don't know how to + * handle vector selects. + * + * See also: + * - http://lists.cs.uiuc.edu/pipermail/llvmdev/2011-October/043659.html */ /* Convert the mask to a vector of booleans. |