Mesa (master): gallium/radeon: cleanup and fix branch emits
Nicolai Hähnle
nh at kemper.freedesktop.org
Tue Oct 4 14:40:40 UTC 2016
Module: Mesa
Branch: master
Commit: 6f87d7a14699277be6dd17e9e712841c4057c4df
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=6f87d7a14699277be6dd17e9e712841c4057c4df
Author: Nicolai Hähnle <nicolai.haehnle at amd.com>
Date: Wed Sep 28 18:20:32 2016 +0200
gallium/radeon: cleanup and fix branch emits
Some of the existing code is needlessly complicated. The basic principle
should be: control-flow opcodes emit branches to properly terminate the
current block, _unless_ the current block already has a terminator (which
happens if and only if there was a BRK or CONT).
This also fixes a bug where multiple terminators were created in a block.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97887
Cc: mesa-stable at lists.freedesktop.org
Reviewed-by: Marek Olšák <marek.olsak at amd.com>
---
.../drivers/radeon/radeon_setup_tgsi_llvm.c | 51 ++++++----------------
1 file changed, 14 insertions(+), 37 deletions(-)
diff --git a/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c b/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
index bcb3143..201bed8 100644
--- a/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
+++ b/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
@@ -796,6 +796,16 @@ void radeon_llvm_emit_store(struct lp_build_tgsi_context *bld_base,
}
}
+/* Emit a branch to the given default target for the current block if
+ * applicable -- that is, if the current block does not already contain a
+ * branch from a break or continue.
+ */
+static void emit_default_branch(LLVMBuilderRef builder, LLVMBasicBlockRef target)
+{
+ if (!LLVMGetBasicBlockTerminator(LLVMGetInsertBlock(builder)))
+ LLVMBuildBr(builder, target);
+}
+
static void bgnloop_emit(const struct lp_build_tgsi_action *action,
struct lp_build_tgsi_context *bld_base,
struct lp_build_emit_data *emit_data)
@@ -856,28 +866,8 @@ static void else_emit(const struct lp_build_tgsi_action *action,
struct radeon_llvm_context *ctx = radeon_llvm_context(bld_base);
struct gallivm_state *gallivm = bld_base->base.gallivm;
struct radeon_llvm_branch *current_branch = get_current_branch(ctx);
- LLVMBasicBlockRef current_block = LLVMGetInsertBlock(gallivm->builder);
-
- /* We need to add a terminator to the current block if the previous
- * instruction was an ENDIF.Example:
- * IF
- * [code]
- * IF
- * [code]
- * ELSE
- * [code]
- * ENDIF <--
- * ELSE<--
- * [code]
- * ENDIF
- */
- if (current_block != current_branch->if_block) {
- LLVMBuildBr(gallivm->builder, current_branch->endif_block);
- }
- if (!LLVMGetBasicBlockTerminator(current_branch->if_block)) {
- LLVMBuildBr(gallivm->builder, current_branch->endif_block);
- }
+ emit_default_branch(gallivm->builder, current_branch->endif_block);
current_branch->has_else = 1;
LLVMPositionBuilderAtEnd(gallivm->builder, current_branch->else_block);
}
@@ -889,26 +879,15 @@ static void endif_emit(const struct lp_build_tgsi_action *action,
struct radeon_llvm_context *ctx = radeon_llvm_context(bld_base);
struct gallivm_state *gallivm = bld_base->base.gallivm;
struct radeon_llvm_branch *current_branch = get_current_branch(ctx);
- LLVMBasicBlockRef current_block = LLVMGetInsertBlock(gallivm->builder);
- /* If we have consecutive ENDIF instructions, then the first ENDIF
- * will not have a terminator, so we need to add one. */
- if (current_block != current_branch->if_block
- && current_block != current_branch->else_block
- && !LLVMGetBasicBlockTerminator(current_block)) {
+ emit_default_branch(gallivm->builder, current_branch->endif_block);
- LLVMBuildBr(gallivm->builder, current_branch->endif_block);
- }
+ /* Need to fixup an empty else block if there was no ELSE opcode. */
if (!LLVMGetBasicBlockTerminator(current_branch->else_block)) {
LLVMPositionBuilderAtEnd(gallivm->builder, current_branch->else_block);
LLVMBuildBr(gallivm->builder, current_branch->endif_block);
}
- if (!LLVMGetBasicBlockTerminator(current_branch->if_block)) {
- LLVMPositionBuilderAtEnd(gallivm->builder, current_branch->if_block);
- LLVMBuildBr(gallivm->builder, current_branch->endif_block);
- }
-
LLVMPositionBuilderAtEnd(gallivm->builder, current_branch->endif_block);
ctx->branch_depth--;
}
@@ -921,9 +900,7 @@ static void endloop_emit(const struct lp_build_tgsi_action *action,
struct gallivm_state *gallivm = bld_base->base.gallivm;
struct radeon_llvm_loop *current_loop = get_current_loop(ctx);
- if (!LLVMGetBasicBlockTerminator(LLVMGetInsertBlock(gallivm->builder))) {
- LLVMBuildBr(gallivm->builder, current_loop->loop_block);
- }
+ emit_default_branch(gallivm->builder, current_loop->loop_block);
LLVMPositionBuilderAtEnd(gallivm->builder, current_loop->endloop_block);
ctx->loop_depth--;
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