i965/fs: Eliminate the magic nature of virtual GRF 0.

This was a debugging aid at one point -- virtual grf 0 should never be
allocated, and it would be used if undefined register access occurred
in codegen.  However, it made the confusing register allocation code
even more confusing by indexing things off of 1 all over.

1 files changed, 3 insertions, 6 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index f55be022f72..d57a67cc4fc 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -181,9 +181,6 @@ fs_visitor::virtual_grf_alloc(int size)
 	 virtual_grf_array_size *= 2;
       virtual_grf_sizes = reralloc(mem_ctx, virtual_grf_sizes, int,
 				   virtual_grf_array_size);
-
-      /* This slot is always unused. */
-      virtual_grf_sizes[0] = 0;
    }
    virtual_grf_sizes[virtual_grf_next] = size;
    return virtual_grf_next++;
@@ -985,7 +982,7 @@ fs_visitor::calculate_live_intervals()
 	 }
       } else {
 	 for (unsigned int i = 0; i < 3; i++) {
-	    if (inst->src[i].file == GRF && inst->src[i].reg != 0) {
+	    if (inst->src[i].file == GRF) {
 	       int reg = inst->src[i].reg;
 
 	       if (!loop_depth) {
@@ -1001,7 +998,7 @@ fs_visitor::calculate_live_intervals()
 	       }
 	    }
 	 }
-	 if (inst->dst.file == GRF && inst->dst.reg != 0) {
+	 if (inst->dst.file == GRF) {
 	    int reg = inst->dst.reg;
 
 	    if (!loop_depth) {
@@ -1715,7 +1712,7 @@ fs_visitor::run()
       if (0) {
 	 /* Debug of register spilling: Go spill everything. */
 	 int virtual_grf_count = virtual_grf_next;
-	 for (int i = 1; i < virtual_grf_count; i++) {
+	 for (int i = 0; i < virtual_grf_count; i++) {
 	    spill_reg(i);
 	 }
       }