ac/llvm: add better code for isign
There are 2 improvements:
- select v_med3_i32
- support vectors
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6284>
diff --git a/src/amd/llvm/ac_llvm_build.c b/src/amd/llvm/ac_llvm_build.c
index de90916..a3fa30f 100644
--- a/src/amd/llvm/ac_llvm_build.c
+++ b/src/amd/llvm/ac_llvm_build.c
@@ -2751,19 +2751,29 @@
AC_FUNC_ATTR_READNONE);
}
-LLVMValueRef ac_build_isign(struct ac_llvm_context *ctx, LLVMValueRef src0,
- unsigned bitsize)
+static LLVMValueRef ac_const_uint_vec(struct ac_llvm_context *ctx, LLVMTypeRef type, uint64_t value)
{
- LLVMTypeRef type = LLVMIntTypeInContext(ctx->context, bitsize);
- LLVMValueRef zero = LLVMConstInt(type, 0, false);
- LLVMValueRef one = LLVMConstInt(type, 1, false);
- LLVMValueRef cmp, val;
- cmp = LLVMBuildICmp(ctx->builder, LLVMIntSGT, src0, zero, "");
- val = LLVMBuildSelect(ctx->builder, cmp, one, src0, "");
- cmp = LLVMBuildICmp(ctx->builder, LLVMIntSGE, val, zero, "");
- val = LLVMBuildSelect(ctx->builder, cmp, val, LLVMConstInt(type, -1, true), "");
- return val;
+ if (LLVMGetTypeKind(type) == LLVMVectorTypeKind) {
+ LLVMValueRef scalar = LLVMConstInt(LLVMGetElementType(type), value, 0);
+ unsigned vec_size = LLVMGetVectorSize(type);
+ LLVMValueRef *scalars = alloca(vec_size * sizeof(LLVMValueRef*));
+
+ for (unsigned i = 0; i < vec_size; i++)
+ scalars[i] = scalar;
+ return LLVMConstVector(scalars, vec_size);
+ }
+ return LLVMConstInt(type, value, 0);
+}
+
+LLVMValueRef ac_build_isign(struct ac_llvm_context *ctx, LLVMValueRef src0)
+{
+ LLVMTypeRef type = LLVMTypeOf(src0);
+ LLVMValueRef val;
+
+ /* v_med3 is selected only when max is first. (LLVM bug?) */
+ val = ac_build_imax(ctx, src0, ac_const_uint_vec(ctx, type, -1));
+ return ac_build_imin(ctx, val, ac_const_uint_vec(ctx, type, 1));
}
LLVMValueRef ac_build_fsign(struct ac_llvm_context *ctx, LLVMValueRef src0,
diff --git a/src/amd/llvm/ac_llvm_build.h b/src/amd/llvm/ac_llvm_build.h
index 764b056..7cb98d0 100644
--- a/src/amd/llvm/ac_llvm_build.h
+++ b/src/amd/llvm/ac_llvm_build.h
@@ -597,10 +597,7 @@
LLVMValueRef ac_build_fract(struct ac_llvm_context *ctx, LLVMValueRef src0,
unsigned bitsize);
-
-LLVMValueRef ac_build_isign(struct ac_llvm_context *ctx, LLVMValueRef src0,
- unsigned bitsize);
-
+LLVMValueRef ac_build_isign(struct ac_llvm_context *ctx, LLVMValueRef src0);
LLVMValueRef ac_build_fsign(struct ac_llvm_context *ctx, LLVMValueRef src0,
unsigned bitsize);
diff --git a/src/amd/llvm/ac_nir_to_llvm.c b/src/amd/llvm/ac_nir_to_llvm.c
index 9ad16fb..ddea781 100644
--- a/src/amd/llvm/ac_nir_to_llvm.c
+++ b/src/amd/llvm/ac_nir_to_llvm.c
@@ -822,8 +822,7 @@
result = ac_build_umin(&ctx->ac, src[0], src[1]);
break;
case nir_op_isign:
- result = ac_build_isign(&ctx->ac, src[0],
- instr->dest.dest.ssa.bit_size);
+ result = ac_build_isign(&ctx->ac, src[0]);
break;
case nir_op_fsign:
src[0] = ac_to_float(&ctx->ac, src[0]);
