Zebediah Figura : vkd3d-shader/hlsl: Handle early return after a CF block only if there was actually a return somewhere in the CF block.
Module: vkd3d Branch: master Commit: 38964214cd65cd429e7882b3f848e8f8966d56a9 URL: https://gitlab.winehq.org/wine/vkd3d/-/commit/38964214cd65cd429e7882b3f848e8... Author: Zebediah Figura <zfigura(a)codeweavers.com> Date: Mon Sep 13 23:48:38 2021 -0500 vkd3d-shader/hlsl: Handle early return after a CF block only if there was actually a return somewhere in the CF block. --- libs/vkd3d-shader/hlsl_codegen.c | 65 ++++++++++++++++++++++++---------------- 1 file changed, 39 insertions(+), 26 deletions(-) diff --git a/libs/vkd3d-shader/hlsl_codegen.c b/libs/vkd3d-shader/hlsl_codegen.c index 2e5feff1..80d52dfc 100644 --- a/libs/vkd3d-shader/hlsl_codegen.c +++ b/libs/vkd3d-shader/hlsl_codegen.c @@ -520,11 +520,12 @@ static void insert_early_return_break(struct hlsl_ctx *ctx, } /* Remove HLSL_IR_JUMP_RETURN calls by altering subsequent control flow. */ -static void lower_return(struct hlsl_ctx *ctx, struct hlsl_ir_function_decl *func, +static bool lower_return(struct hlsl_ctx *ctx, struct hlsl_ir_function_decl *func, struct hlsl_block *block, bool in_loop) { struct hlsl_ir_node *return_instr = NULL, *cf_instr = NULL; struct hlsl_ir_node *instr, *next; + bool has_early_return = false; /* SM1 has no function calls. SM4 does, but native d3dcompiler inlines * everything anyway. We are safest following suit. @@ -546,7 +547,7 @@ static void lower_return(struct hlsl_ctx *ctx, struct hlsl_ir_function_decl *fun * return into a break, which offers the right semantics—except that it * won't break out of nested loops. * - * - A CF block which might contain a return statement. After calling + * - A CF block which contains a return statement. After calling * lower_return() on the CF block body, we stop, pull out everything after * the CF instruction, shove it into an if block, and then lower that if * block. @@ -559,6 +560,9 @@ static void lower_return(struct hlsl_ctx *ctx, struct hlsl_ir_function_decl *fun * already turned any returns into breaks. If the block we just processed * was conditional, then "break" did our work for us. If it was a loop, * we need to propagate that break to the outer loop. + * + * We return true if there was an early return anywhere in the block we just + * processed (including CF contained inside that block). */ LIST_FOR_EACH_ENTRY_SAFE(instr, next, &block->instrs, struct hlsl_ir_node, entry) @@ -573,32 +577,38 @@ static void lower_return(struct hlsl_ctx *ctx, struct hlsl_ir_function_decl *fun { struct hlsl_ir_if *iff = hlsl_ir_if(instr); - lower_return(ctx, func, &iff->then_instrs, in_loop); - lower_return(ctx, func, &iff->else_instrs, in_loop); + has_early_return |= lower_return(ctx, func, &iff->then_instrs, in_loop); + has_early_return |= lower_return(ctx, func, &iff->else_instrs, in_loop); - /* If we're in a loop, we don't need to do anything here. We - * turned the return into a break, and that will already skip - * anything that comes after this "if" block. */ - if (!in_loop) + if (has_early_return) { - cf_instr = instr; - break; + /* If we're in a loop, we don't need to do anything here. We + * turned the return into a break, and that will already skip + * anything that comes after this "if" block. */ + if (!in_loop) + { + cf_instr = instr; + break; + } } } else if (instr->type == HLSL_IR_LOOP) { - lower_return(ctx, func, &hlsl_ir_loop(instr)->body, true); + has_early_return |= lower_return(ctx, func, &hlsl_ir_loop(instr)->body, true); - if (in_loop) - { - /* "instr" is a nested loop. "return" breaks out of all - * loops, so break out of this one too now. */ - insert_early_return_break(ctx, func, instr); - } - else + if (has_early_return) { - cf_instr = instr; - break; + if (in_loop) + { + /* "instr" is a nested loop. "return" breaks out of all + * loops, so break out of this one too now. */ + insert_early_return_break(ctx, func, instr); + } + else + { + cf_instr = instr; + break; + } } } else if (instr->type == HLSL_IR_JUMP) @@ -610,13 +620,14 @@ static void lower_return(struct hlsl_ctx *ctx, struct hlsl_ir_function_decl *fun if (jump->type == HLSL_IR_JUMP_RETURN) { if (!(constant = hlsl_new_bool_constant(ctx, true, &jump->node.loc))) - return; + return false; list_add_before(&jump->node.entry, &constant->node.entry); if (!(store = hlsl_new_simple_store(ctx, func->early_return_var, &constant->node))) - return; + return false; list_add_after(&constant->node.entry, &store->node.entry); + has_early_return = true; if (in_loop) { jump->type = HLSL_IR_JUMP_BREAK; @@ -658,24 +669,26 @@ static void lower_return(struct hlsl_ctx *ctx, struct hlsl_ir_function_decl *fun assert(!in_loop); if (tail == &cf_instr->entry) - return; + return has_early_return; if (!(load = hlsl_new_var_load(ctx, func->early_return_var, cf_instr->loc))) - return; + return false; list_add_tail(&block->instrs, &load->node.entry); if (!(not = hlsl_new_unary_expr(ctx, HLSL_OP1_LOGIC_NOT, &load->node, cf_instr->loc))) - return; + return false; list_add_tail(&block->instrs, ¬->entry); if (!(iff = hlsl_new_if(ctx, not, cf_instr->loc))) - return; + return false; list_add_tail(&block->instrs, &iff->node.entry); list_move_slice_tail(&iff->then_instrs.instrs, list_next(&block->instrs, &cf_instr->entry), tail); lower_return(ctx, func, &iff->then_instrs, in_loop); } + + return has_early_return; } /* Remove HLSL_IR_CALL instructions by inlining them. */
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Alexandre Julliard