intel/fs: Bail in optimize_extract_to_float if we have modifiers

This fixes a bug in runscape where we were optimizing x >> 16 to an
extract and then negating and converting to float.  The NIR to fs pass
was dropping the negate on the floor breaking a geometry shader and
causing it to render nothing.

Fixes: 1f862e923cb "i965/fs: Optimize float conversions of byte/word..."
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109601
Tested-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>

diff --git a/src/intel/compiler/brw_fs_nir.cpp b/src/intel/compiler/brw_fs_nir.cpp
index a24e880..02f1e55 100644 (file)
--- a/src/intel/compiler/brw_fs_nir.cpp
+++ b/src/intel/compiler/brw_fs_nir.cpp
@@ -512,6 +512,15 @@ fs_visitor::optimize_extract_to_float(nir_alu_instr *instr,
        src0->op != nir_op_extract_i8 && src0->op != nir_op_extract_i16)
       return false;
 
+   /* If either opcode has source modifiers, bail.
+    *
+    * TODO: We can potentially handle source modifiers if both of the opcodes
+    * we're combining are signed integers.
+    */
+   if (instr->src[0].abs || instr->src[0].negate ||
+       src0->src[0].abs || src0->src[0].negate)
+      return false;
+
    unsigned element = nir_src_as_uint(src0->src[1].src);
 
    /* Element type to extract.*/