Mesa (main): ac/llvm: implement byte/word extract/insert instructions

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Module: Mesa
Branch: main
Commit: 7d76b07d6bc3572695a7b74bf0c6c160911160e3
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=7d76b07d6bc3572695a7b74bf0c6c160911160e3

Author: Rhys Perry <pendingchaos02 at gmail.com>
Date:   Wed Oct 28 13:32:25 2020 +0000

ac/llvm: implement byte/word extract/insert instructions

Signed-off-by: Rhys Perry <pendingchaos02 at gmail.com>
Reviewed-by: Timur Kristóf <timur.kristof at gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3151>

---

 src/amd/llvm/ac_nir_to_llvm.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/src/amd/llvm/ac_nir_to_llvm.c b/src/amd/llvm/ac_nir_to_llvm.c
index f2173376cce..f58a5a128d5 100644
--- a/src/amd/llvm/ac_nir_to_llvm.c
+++ b/src/amd/llvm/ac_nir_to_llvm.c
@@ -1211,6 +1211,31 @@ static void visit_alu(struct ac_nir_context *ctx, const nir_alu_instr *instr)
       break;
    }
 
+   case nir_op_extract_u8:
+   case nir_op_extract_i8:
+   case nir_op_extract_u16:
+   case nir_op_extract_i16: {
+      bool is_signed = instr->op == nir_op_extract_i16 || instr->op == nir_op_extract_i8;
+      unsigned size = instr->op == nir_op_extract_u8 || instr->op == nir_op_extract_i8 ? 8 : 16;
+      LLVMValueRef offset = LLVMConstInt(LLVMTypeOf(src[0]), nir_src_as_uint(instr->src[1].src) * size, false);
+      result = LLVMBuildLShr(ctx->ac.builder, src[0], offset, "");
+      result = LLVMBuildTrunc(ctx->ac.builder, result, LLVMIntTypeInContext(ctx->ac.context, size), "");
+      if (is_signed)
+         result = LLVMBuildSExt(ctx->ac.builder, result, LLVMTypeOf(src[0]), "");
+      else
+         result = LLVMBuildZExt(ctx->ac.builder, result, LLVMTypeOf(src[0]), "");
+      break;
+   }
+
+   case nir_op_insert_u8:
+   case nir_op_insert_u16: {
+      unsigned size = instr->op == nir_op_insert_u8 ? 8 : 16;
+      LLVMValueRef offset = LLVMConstInt(LLVMTypeOf(src[0]), nir_src_as_uint(instr->src[1].src) * size, false);
+      LLVMValueRef mask = LLVMConstInt(LLVMTypeOf(src[0]), u_bit_consecutive(0, size), false);
+      result = LLVMBuildShl(ctx->ac.builder, LLVMBuildAnd(ctx->ac.builder, src[0], mask, ""), offset, "");
+      break;
+   }
+
    default:
       fprintf(stderr, "Unknown NIR alu instr: ");
       nir_print_instr(&instr->instr, stderr);