diff options
Diffstat (limited to 'src/glsl/lower_instructions.cpp')
| -rw-r--r-- | src/glsl/lower_instructions.cpp | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/src/glsl/lower_instructions.cpp b/src/glsl/lower_instructions.cpp index 0d9374d73b..a5f61f213d 100644 --- a/src/glsl/lower_instructions.cpp +++ b/src/glsl/lower_instructions.cpp @@ -33,6 +33,7 @@ * - SUB_TO_ADD_NEG * - DIV_TO_MUL_RCP * - EXP_TO_EXP2 + * - POW_TO_EXP2 * - LOG_TO_LOG2 * - MOD_TO_FRACT * @@ -61,6 +62,11 @@ * do have base 2 versions, so this pass converts exp and log to exp2 * and log2 operations. * + * POW_TO_EXP2: + * ----------- + * Many older GPUs don't have an x**y instruction. For these GPUs, convert + * x**y to 2**(y * log2(x)). + * * MOD_TO_FRACT: * ------------- * Breaks an ir_unop_mod expression down to (op1 * fract(op0 / op1)) @@ -91,6 +97,7 @@ private: void div_to_mul_rcp(ir_expression *); void mod_to_fract(ir_expression *); void exp_to_exp2(ir_expression *); + void pow_to_exp2(ir_expression *); void log_to_log2(ir_expression *); }; @@ -181,6 +188,20 @@ lower_instructions_visitor::exp_to_exp2(ir_expression *ir) } void +lower_instructions_visitor::pow_to_exp2(ir_expression *ir) +{ + ir_expression *const log2_x = + new(ir) ir_expression(ir_unop_log2, ir->operands[0]->type, + ir->operands[0]); + + ir->operation = ir_unop_exp2; + ir->operands[0] = new(ir) ir_expression(ir_binop_mul, ir->operands[1]->type, + ir->operands[1], log2_x); + ir->operands[1] = NULL; + this->progress = true; +} + +void lower_instructions_visitor::log_to_log2(ir_expression *ir) { ir->operation = ir_binop_mul; @@ -254,6 +275,11 @@ lower_instructions_visitor::visit_leave(ir_expression *ir) mod_to_fract(ir); break; + case ir_binop_pow: + if (lowering(POW_TO_EXP2)) + pow_to_exp2(ir); + break; + default: return visit_continue; } |