nvc0/ir: fix overwriting of value backing non-constant gather offset

Normally the value is an immediate, which is moved to some temporary, so
there's no problem. In the case of a non-constant offset (as allowed by
ARB_gpu_shader5), we have to take care to copy it first before using it
to build up the bits.

This fixes a compilation error observed in F1 2015.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Cc: mesa-stable@lists.freedesktop.org

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
index 3c3d611..4c013c4 100644 (file)
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
@@ -820,11 +820,11 @@ NVC0LoweringPass::handleTEX(TexInstruction *i)
          // Either there is 1 offset, which goes into the 2 low bytes of the
          // first source, or there are 4 offsets, which go into 2 sources (8
          // values, 1 byte each).
-         Value *offs[2] = {NULL, NULL};
+         Value *offs[2] = {bld.getScratch(), bld.getScratch()};
          for (n = 0; n < i->tex.useOffsets; n++) {
             for (c = 0; c < 2; ++c) {
                if ((n % 2) == 0 && c == 0)
-                  offs[n / 2] = i->offset[n][c].get();
+                  bld.mkMov(offs[n / 2], i->offset[n][c].get());
                else
                   bld.mkOp3(OP_INSBF, TYPE_U32,
                             offs[n / 2],