From: Michel Dänzer <michel.daenzer@amd.com>
Date: Wed, 13 Feb 2013 14:57:23 +0000 (+0100)
Subject: radeonsi: Fix w component of TGSI_SEMANTIC_POSITION fragment shader inputs.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=954bc4ac34b821cdc4ecb3ea8e394a66bcc2dda0;p=mesa.git

radeonsi: Fix w component of TGSI_SEMANTIC_POSITION fragment shader inputs.

It's the reciprocal of the register value.

Fixes piglit fragcoord_w and glsl-fs-fragcoord-zw-perspective.

NOTE: This is a candidate for the 9.1 branch.
---

diff --git a/src/gallium/drivers/radeonsi/radeonsi_shader.c b/src/gallium/drivers/radeonsi/radeonsi_shader.c
index 704f859efd7..7922928043f 100644
--- a/src/gallium/drivers/radeonsi/radeonsi_shader.c
+++ b/src/gallium/drivers/radeonsi/radeonsi_shader.c
@@ -263,6 +263,14 @@ static void declare_input_fs(
 				build_intrinsic(base->gallivm->builder,
 					"llvm.SI.fs.read.pos", input_type,
 					args, 1, LLVMReadNoneAttribute);
+
+			if (chan == 3)
+				/* RCP for fragcoord.w */
+				si_shader_ctx->radeon_bld.inputs[soa_index] =
+					LLVMBuildFDiv(gallivm->builder,
+						      lp_build_const_float(gallivm, 1.0f),
+						      si_shader_ctx->radeon_bld.inputs[soa_index],
+						      "");
 		}
 		return;
 	}