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authorSamuel Pitoiset <samuel.pitoiset@gmail.com>2018-07-19 20:27:11 +0200
committerSamuel Pitoiset <samuel.pitoiset@gmail.com>2018-07-19 20:41:10 +0200
commit3d41757788aca774e64297bed962696cc0c9b262 (patch)
treeee88fde9cbaa3d53c40baa9a41467a553ee2e5d3
parente2e32b6afd4cd1cd091877b638288e861a537760 (diff)
ac/nir: add a workaround for bitfield_extract when count is 0
LLVM 7 returns incorrect results when count is 0, something has been broken since LLVM 6. Of course, the best solution is to fix LLVM but this workaround works as expected for now. Original workaround by Philippe Rebohle. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107276 Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com> Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
-rw-r--r--src/amd/common/ac_nir_to_llvm.c20
1 files changed, 17 insertions, 3 deletions
diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_llvm.c
index 83d8b9a4425..10d17738509 100644
--- a/src/amd/common/ac_nir_to_llvm.c
+++ b/src/amd/common/ac_nir_to_llvm.c
@@ -418,10 +418,24 @@ static LLVMValueRef emit_bitfield_extract(struct ac_llvm_context *ctx,
const LLVMValueRef srcs[3])
{
LLVMValueRef result;
- LLVMValueRef icond = LLVMBuildICmp(ctx->builder, LLVMIntEQ, srcs[2], LLVMConstInt(ctx->i32, 32, false), "");
- result = ac_build_bfe(ctx, srcs[0], srcs[1], srcs[2], is_signed);
- result = LLVMBuildSelect(ctx->builder, icond, srcs[0], result, "");
+ if (HAVE_LLVM < 0x0700) {
+ LLVMValueRef icond = LLVMBuildICmp(ctx->builder, LLVMIntEQ, srcs[2], LLVMConstInt(ctx->i32, 32, false), "");
+ result = ac_build_bfe(ctx, srcs[0], srcs[1], srcs[2], is_signed);
+ result = LLVMBuildSelect(ctx->builder, icond, srcs[0], result, "");
+ } else {
+ /* FIXME: LLVM 7 returns incorrect result when count is 0.
+ * https://bugs.freedesktop.org/show_bug.cgi?id=107276
+ */
+ LLVMValueRef zero = LLVMConstInt(ctx->i32, 0, false);
+ LLVMValueRef icond1 = LLVMBuildICmp(ctx->builder, LLVMIntEQ, srcs[2], LLVMConstInt(ctx->i32, 32, false), "");
+ LLVMValueRef icond2 = LLVMBuildICmp(ctx->builder, LLVMIntEQ, srcs[2], zero, "");
+
+ result = ac_build_bfe(ctx, srcs[0], srcs[1], srcs[2], is_signed);
+ result = LLVMBuildSelect(ctx->builder, icond1, srcs[0], result, "");
+ result = LLVMBuildSelect(ctx->builder, icond2, zero, result, "");
+ }
+
return result;
}