From 63b4fcba33848029e7dd1476d9f82070308a7239 Mon Sep 17 00:00:00 2001 From: Neil Roberts Date: Thu, 2 Apr 2020 16:25:18 +0200 Subject: [PATCH] glsl/lower_precision: Use vector.back() instead of vector.end()[-1] MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The use of vector.end()[-1] seems to generate warnings in Coverity about not allowing a negative argument to a parameter. The intention with the code snippet is just to access the last element of the vector. The vector.back() call acheives the same thing, is clearer and will hopefully fix the Coverity warning. I’m not exactly sure why Coverity thinks the array index can’t be negative. cplusplus.com says that vector::end() returns a random access iterator and that the type of the array index operator argument to that should be the difference type for the container. It then also says that difference_type for a vector is "a signed integral type". Reviewed-by: Eric Anholt --- src/compiler/glsl/lower_precision.cpp | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/src/compiler/glsl/lower_precision.cpp b/src/compiler/glsl/lower_precision.cpp index 4e4ef8ef2e5..332cd50cc7a 100644 --- a/src/compiler/glsl/lower_precision.cpp +++ b/src/compiler/glsl/lower_precision.cpp @@ -200,7 +200,7 @@ find_lowerable_rvalues_visitor::add_lowerable_children(const stack_entry &entry) void find_lowerable_rvalues_visitor::pop_stack_entry() { - const stack_entry &entry = stack.end()[-1]; + const stack_entry &entry = stack.back(); if (stack.size() >= 2) { /* Combine this state into the parent state, unless the parent operation @@ -315,7 +315,7 @@ find_lowerable_rvalues_visitor::visit(ir_constant *ir) stack_enter(ir, this); if (!can_lower_type(ir->type)) - stack.end()[-1].state = CANT_LOWER; + stack.back().state = CANT_LOWER; stack_leave(ir, this); @@ -327,8 +327,8 @@ find_lowerable_rvalues_visitor::visit(ir_dereference_variable *ir) { stack_enter(ir, this); - if (stack.end()[-1].state == UNKNOWN) - stack.end()[-1].state = handle_precision(ir->type, ir->precision()); + if (stack.back().state == UNKNOWN) + stack.back().state = handle_precision(ir->type, ir->precision()); stack_leave(ir, this); @@ -340,8 +340,8 @@ find_lowerable_rvalues_visitor::visit_enter(ir_dereference_record *ir) { ir_hierarchical_visitor::visit_enter(ir); - if (stack.end()[-1].state == UNKNOWN) - stack.end()[-1].state = handle_precision(ir->type, ir->precision()); + if (stack.back().state == UNKNOWN) + stack.back().state = handle_precision(ir->type, ir->precision()); return visit_continue; } @@ -351,8 +351,8 @@ find_lowerable_rvalues_visitor::visit_enter(ir_dereference_array *ir) { ir_hierarchical_visitor::visit_enter(ir); - if (stack.end()[-1].state == UNKNOWN) - stack.end()[-1].state = handle_precision(ir->type, ir->precision()); + if (stack.back().state == UNKNOWN) + stack.back().state = handle_precision(ir->type, ir->precision()); return visit_continue; } @@ -362,12 +362,12 @@ find_lowerable_rvalues_visitor::visit_enter(ir_texture *ir) { ir_hierarchical_visitor::visit_enter(ir); - if (stack.end()[-1].state == UNKNOWN) { + if (stack.back().state == UNKNOWN) { /* The precision of the sample value depends on the precision of the * sampler. */ - stack.end()[-1].state = handle_precision(ir->type, - ir->sampler->precision()); + stack.back().state = handle_precision(ir->type, + ir->sampler->precision()); } return visit_continue; @@ -379,7 +379,7 @@ find_lowerable_rvalues_visitor::visit_enter(ir_expression *ir) ir_hierarchical_visitor::visit_enter(ir); if (!can_lower_type(ir->type)) - stack.end()[-1].state = CANT_LOWER; + stack.back().state = CANT_LOWER; /* Don't lower precision for derivative calculations */ if (ir->operation == ir_unop_dFdx || @@ -388,7 +388,7 @@ find_lowerable_rvalues_visitor::visit_enter(ir_expression *ir) ir->operation == ir_unop_dFdy || ir->operation == ir_unop_dFdy_coarse || ir->operation == ir_unop_dFdy_fine) { - stack.end()[-1].state = CANT_LOWER; + stack.back().state = CANT_LOWER; } return visit_continue; -- 2.30.2