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ac/llvm: Add LLVM bug workaround to ac_build_mbcnt_add. 

LLVM always believes that this instruction's upper bound is the wave
size, regardless of ac_set_range_metadata and regardless of whether
the add source is used.

As a workaround, emit an extra add instruction.

Cc: mesa-stable
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Qiang Yu <yuq825@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17706>
This commit is contained in:
Timur Kristóf 2022-05-19 23:13:28 +02:00 committed by Marge Bot
parent c9f8be9d58
commit 1e2663b62c
1 changed files with 20 additions and 13 deletions
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33
src/amd/llvm/ac_llvm_build.c
View File

@ -3220,21 +3220,28 @@ LLVMValueRef ac_build_writelane(struct ac_llvm_context *ctx, LLVMValueRef src, L
LLVMValueRef ac_build_mbcnt_add(struct ac_llvm_context *ctx, LLVMValueRef mask, LLVMValueRef add_src)
{
LLVMValueRef val;
if (ctx->wave_size == 32) {
LLVMValueRef val = ac_build_intrinsic(ctx, "llvm.amdgcn.mbcnt.lo", ctx->i32,
(LLVMValueRef[]){mask, add_src}, 2, AC_FUNC_ATTR_READNONE);
ac_set_range_metadata(ctx, val, 0, ctx->wave_size);
return val;
val = ac_build_intrinsic(ctx, "llvm.amdgcn.mbcnt.lo", ctx->i32,
(LLVMValueRef[]){mask, ctx->i32_0}, 2, AC_FUNC_ATTR_READNONE);
} else {
LLVMValueRef mask_vec = LLVMBuildBitCast(ctx->builder, mask, ctx->v2i32, "");
LLVMValueRef mask_lo = LLVMBuildExtractElement(ctx->builder, mask_vec, ctx->i32_0, "");
LLVMValueRef mask_hi = LLVMBuildExtractElement(ctx->builder, mask_vec, ctx->i32_1, "");
val = ac_build_intrinsic(ctx, "llvm.amdgcn.mbcnt.lo", ctx->i32,
(LLVMValueRef[]){mask_lo, ctx->i32_0}, 2, AC_FUNC_ATTR_READNONE);
val = ac_build_intrinsic(ctx, "llvm.amdgcn.mbcnt.hi", ctx->i32, (LLVMValueRef[]){mask_hi, val},
2, AC_FUNC_ATTR_READNONE);
}
LLVMValueRef mask_vec = LLVMBuildBitCast(ctx->builder, mask, ctx->v2i32, "");
LLVMValueRef mask_lo = LLVMBuildExtractElement(ctx->builder, mask_vec, ctx->i32_0, "");
LLVMValueRef mask_hi = LLVMBuildExtractElement(ctx->builder, mask_vec, ctx->i32_1, "");
LLVMValueRef val =
ac_build_intrinsic(ctx, "llvm.amdgcn.mbcnt.lo", ctx->i32,
(LLVMValueRef[]){mask_lo, add_src}, 2, AC_FUNC_ATTR_READNONE);
val = ac_build_intrinsic(ctx, "llvm.amdgcn.mbcnt.hi", ctx->i32, (LLVMValueRef[]){mask_hi, val},
2, AC_FUNC_ATTR_READNONE);
ac_set_range_metadata(ctx, val, 0, ctx->wave_size);
/* Bug workaround. LLVM always believes the upper bound of mbcnt to be the wave size,
* regardless of ac_set_range_metadata. Use an extra add instruction to work around it.
*/
if (add_src != NULL && add_src != ctx->i32_0) {
return LLVMBuildAdd(ctx->builder, val, add_src, "");
}
return val;
}