From 7dc449d406a88fbb92aedfacfa3869176ba2cb31 Mon Sep 17 00:00:00 2001 From: Brian Paul Date: Fri, 14 Mar 2008 13:50:01 -0600 Subject: [PATCH] mesa: fix emit_clamp() so that we don't use an output register as temporary IR_CLAMP is decomposed into OPCODE_MIN+OPCODE_MAX. Allocate a temporary register for the intermediate value so we don't inadvertantly use an output register (which are write-only on some GPUs). --- src/mesa/shader/slang/slang_emit.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/src/mesa/shader/slang/slang_emit.c b/src/mesa/shader/slang/slang_emit.c index 2b08e7020f0..3763b567055 100644 --- a/src/mesa/shader/slang/slang_emit.c +++ b/src/mesa/shader/slang/slang_emit.c @@ -677,6 +677,7 @@ static struct prog_instruction * emit_clamp(slang_emit_info *emitInfo, slang_ir_node *n) { struct prog_instruction *inst; + slang_ir_node tmpNode; assert(n->Opcode == IR_CLAMP); /* ch[0] = value @@ -722,18 +723,26 @@ emit_clamp(slang_emit_info *emitInfo, slang_ir_node *n) emit(emitInfo, n->Children[1]); emit(emitInfo, n->Children[2]); + /* Some GPUs don't allow reading from output registers. So if the + * dest for this clamp() is an output reg, we can't use that reg for + * the intermediate result. Use a temp register instead. + */ + alloc_temp_storage(emitInfo, &tmpNode, n->Store->Size); + /* tmp = max(ch[0], ch[1]) */ inst = new_instruction(emitInfo, OPCODE_MAX); - storage_to_dst_reg(&inst->DstReg, n->Store, n->Writemask); + storage_to_dst_reg(&inst->DstReg, tmpNode.Store, n->Writemask); storage_to_src_reg(&inst->SrcReg[0], n->Children[0]->Store); storage_to_src_reg(&inst->SrcReg[1], n->Children[1]->Store); - /* tmp = min(tmp, ch[2]) */ + /* n->dest = min(tmp, ch[2]) */ inst = new_instruction(emitInfo, OPCODE_MIN); storage_to_dst_reg(&inst->DstReg, n->Store, n->Writemask); - storage_to_src_reg(&inst->SrcReg[0], n->Store); + storage_to_src_reg(&inst->SrcReg[0], tmpNode.Store); storage_to_src_reg(&inst->SrcReg[1], n->Children[2]->Store); + free_temp_storage(emitInfo->vt, &tmpNode); + return inst; } -- 2.30.2