Re: [Mesa-dev] [PATCH] i965/fs: New peephole optimization to flatten IF/BREAK/ENDIF.
On 11/05/2013 02:58 PM, Paul Berry wrote: [snip] Instead of this special-purpose peephole optimization, I'm wondering if it would be more useful to create a more general optimization pass that just converts the entire IF block to predicated instructions, assuming certain conditions hold. Those conditions would be something like: - If any instruction but the last writes to the flag register, then don't do the optimization. - If there's nested control flow, then don't do the optimization. - If any instruction inside the IF block is incompatible with predication (are there any such instructions? I don't know) then don't do the optimization. - If the block is larger than a certain heuristically-determined size, then don't do the optimization. Such an optimization could in principle even handle IF/ELSE blocks, by inverting the predicate in the ELSE section. Eric and I actually wrote such a pass...it's sitting on a branch somewhere. At the time, it helped some things massively, but caused a few shaders to explode into spilling. Maybe with the newer scheduling changes, that problem's been solved... --Ken ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH] i965/fs: New peephole optimization to flatten IF/BREAK/ENDIF.
On 1 November 2013 17:31, Matt Turner matts...@gmail.com wrote: total instructions in shared programs: 1649485 - 1649157 (-0.02%) instructions in affected programs: 7823 - 7495 (-4.19%) --- src/mesa/drivers/dri/i965/Makefile.sources | 1 + src/mesa/drivers/dri/i965/brw_fs.cpp | 1 + src/mesa/drivers/dri/i965/brw_fs.h | 1 + .../dri/i965/brw_fs_peephole_predicated_break.cpp | 96 ++ 4 files changed, 99 insertions(+) create mode 100644 src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp diff --git a/src/mesa/drivers/dri/i965/Makefile.sources b/src/mesa/drivers/dri/i965/Makefile.sources index 14b2f61..fcc6fdb 100644 --- a/src/mesa/drivers/dri/i965/Makefile.sources +++ b/src/mesa/drivers/dri/i965/Makefile.sources @@ -59,6 +59,7 @@ i965_FILES = \ brw_fs_fp.cpp \ brw_fs_generator.cpp \ brw_fs_live_variables.cpp \ + brw_fs_peephole_predicated_break.cpp \ brw_fs_reg_allocate.cpp \ brw_fs_vector_splitting.cpp \ brw_fs_visitor.cpp \ diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp index 7064910..5c8443f 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp @@ -3149,6 +3149,7 @@ fs_visitor::run() progress = opt_algebraic() || progress; progress = opt_cse() || progress; progress = opt_copy_propagate() || progress; + progress = opt_peephole_predicated_break() || progress; progress = dead_code_eliminate() || progress; progress = dead_code_eliminate_local() || progress; progress = register_coalesce() || progress; diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h index 43e4761..09e5174 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.h +++ b/src/mesa/drivers/dri/i965/brw_fs.h @@ -362,6 +362,7 @@ public: bool try_emit_saturate(ir_expression *ir); bool try_emit_mad(ir_expression *ir, int mul_arg); void try_replace_with_sel(); + bool opt_peephole_predicated_break(); void emit_bool_to_cond_code(ir_rvalue *condition); void emit_if_gen6(ir_if *ir); void emit_unspill(fs_inst *inst, fs_reg reg, uint32_t spill_offset, diff --git a/src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp b/src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp new file mode 100644 index 000..7845113 --- /dev/null +++ b/src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp @@ -0,0 +1,96 @@ +/* + * Copyright © 2013 Intel Corporation + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the Software), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS + * IN THE SOFTWARE. + */ + +#include brw_fs.h +#include brw_cfg.h + +/** @file brw_fs_peephole_predicated_break.cpp + * + * Loops are often structured as + * + * loop: + *CMP.f0 + *(+f0) IF + *BREAK + *ENDIF + *... + *WHILE loop + * + * This peephole pass removes the IF and ENDIF instructions and predicates the + * BREAK, dropping two instructions from the loop body. Instead of this special-purpose peephole optimization, I'm wondering if it would be more useful to create a more general optimization pass that just converts the entire IF block to predicated instructions, assuming certain conditions hold. Those conditions would be something like: - If any instruction but the last writes to the flag register, then don't do the optimization. - If there's nested control flow, then don't do the optimization. - If any instruction inside the IF block is incompatible with predication (are there any such instructions? I don't know) then don't do the optimization. - If the block is larger than a certain heuristically-determined size, then don't do the optimization. Such an optimization could in principle even handle IF/ELSE blocks, by inverting the predicate
Re: [Mesa-dev] [PATCH] i965/fs: New peephole optimization to flatten IF/BREAK/ENDIF.
On 5 November 2013 14:58, Paul Berry stereotype...@gmail.com wrote: On 1 November 2013 17:31, Matt Turner matts...@gmail.com wrote: total instructions in shared programs: 1649485 - 1649157 (-0.02%) instructions in affected programs: 7823 - 7495 (-4.19%) --- src/mesa/drivers/dri/i965/Makefile.sources | 1 + src/mesa/drivers/dri/i965/brw_fs.cpp | 1 + src/mesa/drivers/dri/i965/brw_fs.h | 1 + .../dri/i965/brw_fs_peephole_predicated_break.cpp | 96 ++ 4 files changed, 99 insertions(+) create mode 100644 src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp diff --git a/src/mesa/drivers/dri/i965/Makefile.sources b/src/mesa/drivers/dri/i965/Makefile.sources index 14b2f61..fcc6fdb 100644 --- a/src/mesa/drivers/dri/i965/Makefile.sources +++ b/src/mesa/drivers/dri/i965/Makefile.sources @@ -59,6 +59,7 @@ i965_FILES = \ brw_fs_fp.cpp \ brw_fs_generator.cpp \ brw_fs_live_variables.cpp \ + brw_fs_peephole_predicated_break.cpp \ brw_fs_reg_allocate.cpp \ brw_fs_vector_splitting.cpp \ brw_fs_visitor.cpp \ diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp index 7064910..5c8443f 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp @@ -3149,6 +3149,7 @@ fs_visitor::run() progress = opt_algebraic() || progress; progress = opt_cse() || progress; progress = opt_copy_propagate() || progress; + progress = opt_peephole_predicated_break() || progress; progress = dead_code_eliminate() || progress; progress = dead_code_eliminate_local() || progress; progress = register_coalesce() || progress; diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h index 43e4761..09e5174 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.h +++ b/src/mesa/drivers/dri/i965/brw_fs.h @@ -362,6 +362,7 @@ public: bool try_emit_saturate(ir_expression *ir); bool try_emit_mad(ir_expression *ir, int mul_arg); void try_replace_with_sel(); + bool opt_peephole_predicated_break(); void emit_bool_to_cond_code(ir_rvalue *condition); void emit_if_gen6(ir_if *ir); void emit_unspill(fs_inst *inst, fs_reg reg, uint32_t spill_offset, diff --git a/src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp b/src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp new file mode 100644 index 000..7845113 --- /dev/null +++ b/src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp @@ -0,0 +1,96 @@ +/* + * Copyright © 2013 Intel Corporation + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the Software), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS + * IN THE SOFTWARE. + */ + +#include brw_fs.h +#include brw_cfg.h + +/** @file brw_fs_peephole_predicated_break.cpp + * + * Loops are often structured as + * + * loop: + *CMP.f0 + *(+f0) IF + *BREAK + *ENDIF + *... + *WHILE loop + * + * This peephole pass removes the IF and ENDIF instructions and predicates the + * BREAK, dropping two instructions from the loop body. Instead of this special-purpose peephole optimization, I'm wondering if it would be more useful to create a more general optimization pass that just converts the entire IF block to predicated instructions, assuming certain conditions hold. Those conditions would be something like: - If any instruction but the last writes to the flag register, then don't do the optimization. - If there's nested control flow, then don't do the optimization. - If any instruction inside the IF block is incompatible with predication (are there any such instructions? I don't know) then don't do the optimization. - If the block is larger than a certain heuristically-determined size, then don't do the optimization. Such an
[Mesa-dev] [PATCH] i965/fs: New peephole optimization to flatten IF/BREAK/ENDIF.
total instructions in shared programs: 1649485 - 1649157 (-0.02%)
instructions in affected programs: 7823 - 7495 (-4.19%)
---
src/mesa/drivers/dri/i965/Makefile.sources | 1 +
src/mesa/drivers/dri/i965/brw_fs.cpp | 1 +
src/mesa/drivers/dri/i965/brw_fs.h | 1 +
.../dri/i965/brw_fs_peephole_predicated_break.cpp | 96 ++
4 files changed, 99 insertions(+)
create mode 100644
src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp
diff --git a/src/mesa/drivers/dri/i965/Makefile.sources
b/src/mesa/drivers/dri/i965/Makefile.sources
index 14b2f61..fcc6fdb 100644
--- a/src/mesa/drivers/dri/i965/Makefile.sources
+++ b/src/mesa/drivers/dri/i965/Makefile.sources
@@ -59,6 +59,7 @@ i965_FILES = \
brw_fs_fp.cpp \
brw_fs_generator.cpp \
brw_fs_live_variables.cpp \
+ brw_fs_peephole_predicated_break.cpp \
brw_fs_reg_allocate.cpp \
brw_fs_vector_splitting.cpp \
brw_fs_visitor.cpp \
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp
b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 7064910..5c8443f 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -3149,6 +3149,7 @@ fs_visitor::run()
progress = opt_algebraic() || progress;
progress = opt_cse() || progress;
progress = opt_copy_propagate() || progress;
+ progress = opt_peephole_predicated_break() || progress;
progress = dead_code_eliminate() || progress;
progress = dead_code_eliminate_local() || progress;
progress = register_coalesce() || progress;
diff --git a/src/mesa/drivers/dri/i965/brw_fs.h
b/src/mesa/drivers/dri/i965/brw_fs.h
index 43e4761..09e5174 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -362,6 +362,7 @@ public:
bool try_emit_saturate(ir_expression *ir);
bool try_emit_mad(ir_expression *ir, int mul_arg);
void try_replace_with_sel();
+ bool opt_peephole_predicated_break();
void emit_bool_to_cond_code(ir_rvalue *condition);
void emit_if_gen6(ir_if *ir);
void emit_unspill(fs_inst *inst, fs_reg reg, uint32_t spill_offset,
diff --git a/src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp
b/src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp
new file mode 100644
index 000..7845113
--- /dev/null
+++ b/src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp
@@ -0,0 +1,96 @@
+/*
+ * Copyright © 2013 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the Software),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include brw_fs.h
+#include brw_cfg.h
+
+/** @file brw_fs_peephole_predicated_break.cpp
+ *
+ * Loops are often structured as
+ *
+ * loop:
+ *CMP.f0
+ *(+f0) IF
+ *BREAK
+ *ENDIF
+ *...
+ *WHILE loop
+ *
+ * This peephole pass removes the IF and ENDIF instructions and predicates the
+ * BREAK, dropping two instructions from the loop body.
+ */
+
+bool
+fs_visitor::opt_peephole_predicated_break()
+{
+ bool progress = false;
+
+ cfg_t cfg(this);
+
+ for (int b = 0; b cfg.num_blocks; b++) {
+ bblock_t *block = cfg.blocks[b];
+
+ /* IF instructions, by definition, can only be found at the ends of
+ * basic blocks.
+ */
+ fs_inst *if_inst = (fs_inst *) block-end;
+ if (if_inst-opcode != BRW_OPCODE_IF)
+ continue;
+
+ fs_inst *inst = (fs_inst *) if_inst-next;
+ if (inst-opcode != BRW_OPCODE_BREAK inst-opcode !=
BRW_OPCODE_CONTINUE)
+ continue;
+
+ fs_inst *endif_inst = (fs_inst *) inst-next;
+ if (endif_inst-opcode != BRW_OPCODE_ENDIF)
+ continue;
+
+ /* For Sandybridge with IF with embedded comparison we need to emit an
+ * instruction to set the flag register.
+ */
+ if (brw-gen == 6 if_inst-conditional_mod) {
+ fs_inst *cmp_inst = CMP(reg_null_d, if_inst-src[0], if_inst-src[1],
+
