glsl: fix another swizzle-related bug

This fixes the case of "infinitely" nested swizzles such as EXPR.wzyx.yxwz.xxyz
This doesn't appear in typical shaders but with function inlining and the
compiler's internal use of swizzles it can happen.
New glean glsl1 test case added for this.

(cherry picked from master, commit d9881356a64b848dbae5fffd77fd93d0eb4247a3)

1 files changed, 8 insertions, 13 deletions

diff --git a/src/mesa/shader/slang/slang_emit.c b/src/mesa/shader/slang/slang_emit.c
index feff1b7474d..db78dbeef6b 100644
--- a/src/mesa/shader/slang/slang_emit.c
+++ b/src/mesa/shader/slang/slang_emit.c
@@ -1360,6 +1360,7 @@ emit_copy(slang_emit_info *emitInfo, slang_ir_node *n)
 
 #if PEEPHOLE_OPTIMIZATIONS
    if (inst &&
+       (n->Children[1]->Opcode != IR_SWIZZLE) &&
        _slang_is_temp(emitInfo->vt, n->Children[1]->Store) &&
        (inst->DstReg.File == n->Children[1]->Store->File) &&
        (inst->DstReg.Index == n->Children[1]->Store->Index) &&
@@ -1376,13 +1377,9 @@ emit_copy(slang_emit_info *emitInfo, slang_ir_node *n)
        * becomes:
        *   MUL a, x, y;
        */
-      if (n->Children[1]->Opcode != IR_SWIZZLE)
-         _slang_free_temp(emitInfo->vt, n->Children[1]->Store);
-      *n->Children[1]->Store = *n->Children[0]->Store;
 
       /* fixup the previous instruction (which stored the RHS result) */
       assert(n->Children[0]->Store->Index >= 0);
-
       storage_to_dst_reg(&inst->DstReg, n->Children[0]->Store);
       return inst;
    }
@@ -1841,24 +1838,22 @@ emit_swizzle(slang_emit_info *emitInfo, slang_ir_node *n)
 
    inst = emit(emitInfo, n->Children[0]);
 
-   if (n->Children[0]->Opcode == IR_VAR ||
-       n->Children[0]->Opcode == IR_SWIZZLE ||
-       n->Children[0]->Opcode == IR_ELEMENT) {
-      /* We can resolve the swizzle now.  Other swizzles will be resolved
-       * in storage_to_src_reg().
-       */
+   assert(n->Children[0]->Store == n->Store->Parent);
+   assert(n->Store->Parent);
+
+   {
       const GLuint swizzle = n->Store->Swizzle;
-      assert(n->Store->Parent);
       /* new storage is parent storage with updated Swizzle + Size fields */
       _slang_copy_ir_storage(n->Store, n->Store->Parent);
       /* Apply this node's swizzle to parent's storage */
       n->Store->Swizzle = _slang_swizzle_swizzle(n->Store->Swizzle, swizzle);
       /* Update size */
       n->Store->Size = swizzle_size(n->Store->Swizzle);
-      assert(!n->Store->Parent);
-      assert(n->Store->Index >= 0);
    }
 
+   assert(!n->Store->Parent);
+   assert(n->Store->Index >= 0);
+
    return inst;
 }