diff mbox series

[v2,3/3] middle-end: add gimple-isel-match.pd

Message ID aljriOtcKBv5vUdI@arm.com
State New
Headers
Series [1/2] middle-end: support namespaces in genmatch |

Commit Message

Tamar Christina July 16, 2026, 2:32 p.m. UTC 
  This commits adds gimple-isel-match.pd which is a match.pd version that only
applies it's rewriting rules at gimple-isel time.  The normal match.pd rules
are also later applied at the end of the pass as normal.

The file is currently empty, but I have some patches to add vector comparisons
matching to this and I noticed a few cases already in isel that can be
simplified using the match.pd machinery.

Bootstrapped Regtested on aarch64-none-linux-gnu,
arm-none-linux-gnueabihf, x86_64-pc-linux-gnu
-m32, -m64 and no issues.

Ok for master?

Thanks,
Tamar

gcc/ChangeLog:

	* Makefile.in: Add entries for gimple-isel-match.pd
	* gimple-isel.cc (gimple_isel_simplify): Forward declare.
	(pass_gimple_isel::execute): Call it.
	* gimple-isel-match.pd: New file.

---


--

Comments

Richard Biener July 28, 2026, 7:41 a.m. UTC | #1 
On Thu, 16 Jul 2026, Tamar Christina wrote:

> This commits adds gimple-isel-match.pd which is a match.pd version that only
> applies it's rewriting rules at gimple-isel time.  The normal match.pd rules
> are also later applied at the end of the pass as normal.
> 
> The file is currently empty, but I have some patches to add vector comparisons
> matching to this and I noticed a few cases already in isel that can be
> simplified using the match.pd machinery.
> 
> Bootstrapped Regtested on aarch64-none-linux-gnu,
> arm-none-linux-gnueabihf, x86_64-pc-linux-gnu
> -m32, -m64 and no issues.
> 
> Ok for master?
> 
> Thanks,
> Tamar
> 
> gcc/ChangeLog:
> 
> 	* Makefile.in: Add entries for gimple-isel-match.pd
> 	* gimple-isel.cc (gimple_isel_simplify): Forward declare.
> 	(pass_gimple_isel::execute): Call it.
> 	* gimple-isel-match.pd: New file.
> 
> ---
> diff --git a/gcc/Makefile.in b/gcc/Makefile.in
> index fa46ada4980ff8fcbdba696f46e81f59b83dc4b4..09fd733c0b80b5c36546f0c54b6a12cc127003fc 100644
> --- a/gcc/Makefile.in
> +++ b/gcc/Makefile.in
> @@ -228,6 +228,10 @@ GIMPLE_MATCH_PD_SEQ_O = $(patsubst %, gimple-match-%.o, $(MATCH_SPLITS_SEQ))
>  GENERIC_MATCH_PD_SEQ_SRC = $(patsubst %, generic-match-%.cc, $(MATCH_SPLITS_SEQ))
>  GENERIC_MATCH_PD_SEQ_O = $(patsubst %, generic-match-%.o, $(MATCH_SPLITS_SEQ))
>  
> +# The number of splits to be made for the gimple-isel-match.pd files.
> +GIMPLE_ISEL_MATCH_PD_SEQ_SRC = $(patsubst %, gimple-isel-match-%.cc, $(MATCH_SPLITS_SEQ))
> +GIMPLE_ISEL_MATCH_PD_SEQ_O = $(patsubst %, gimple-isel-match-%.o, $(MATCH_SPLITS_SEQ))
> +

I think we can avoid splitting this for now?

>  # The number of splits to be made for the insn-emit files.
>  NUM_INSNEMIT_SPLITS = @DEFAULT_INSNEMIT_PARTITIONS@
>  INSNEMIT_SPLITS_SEQ = $(wordlist 1,$(NUM_INSNEMIT_SPLITS),$(one_to_9999))
> @@ -1401,6 +1405,7 @@ ANALYZER_OBJS = \
>  # the last objects to finish building.
>  OBJS = \
>  	$(GIMPLE_MATCH_PD_SEQ_O) \
> +	$(GIMPLE_ISEL_MATCH_PD_SEQ_O) \
>  	gimple-match-exports.o \
>  	$(GENERIC_MATCH_PD_SEQ_O) \
>  	insn-attrtab.o \
> @@ -1987,7 +1992,8 @@ MOSTLYCLEANFILES = insn-flags.h insn-config.h insn-codes.h \
>   insn-attr.h insn-attr-common.h insn-attrtab.cc insn-dfatab.cc \
>   insn-latencytab.cc insn-opinit.cc insn-opinit.h insn-preds.cc insn-constants.h \
>   tm-preds.h tm-constrs.h checksum-options $(GIMPLE_MATCH_PD_SEQ_SRC) \
> - $(GENERIC_MATCH_PD_SEQ_SRC) gimple-match-auto.h generic-match-auto.h \
> + $(GIMPLE_ISEL_MATCH_PD_SEQ_SRC) $(GENERIC_MATCH_PD_SEQ_SRC) \
> + gimple-match-auto.h generic-match-auto.h \
>   tree-check.h min-insn-modes.cc insn-modes.cc insn-modes.h insn-modes-inline.h \
>   genrtl.h gt-*.h gtype-*.h gtype-desc.cc gtyp-input.list \
>   case-cfn-macros.h cfn-operators.pd \
> @@ -2762,6 +2768,7 @@ $(common_out_object_file): $(common_out_file)
>    insn-extract.cc insn-output.cc \
>    insn-peep.cc insn-attr.h insn-attr-common.h insn-attrtab.cc \
>    insn-dfatab.cc insn-latencytab.cc insn-preds.cc \
> +  $(GIMPLE_ISEL_MATCH_PD_SEQ_SRC) \
>    $(GIMPLE_MATCH_PD_SEQ_SRC) $(GENERIC_MATCH_PD_SEQ_SRC) \
>    gimple-match-auto.h generic-match-auto.h insn-target-def.h
>  
> @@ -3077,6 +3084,23 @@ s-generic-match: build/genmatch$(build_exeext) \
>  						generic-match-auto.h
>  	$(STAMP) s-generic-match
>  
> +# Add gimple-isel-match.pd
> +$(GIMPLE_ISEL_MATCH_PD_SEQ_SRC): s-gimple-isel-match gimple-match-head.cc; @true
> +gimple-isel-match-auto.h: s-gimple-isel-match; @true
> +
> +s-gimple-isel-match: build/genmatch$(build_exeext) \
> +	    $(srcdir)/gimple-isel-match.pd cfn-operators.pd
> +	$(RUN_GEN) build/genmatch$(build_exeext) --gimple \
> +	    --header=tmp-gimple-isel-match-auto.h \
> +	    --include=gimple-isel-match-auto.h --namespace=isel \
> +	    $(srcdir)/gimple-isel-match.pd $(patsubst %, tmp-%, $(GIMPLE_ISEL_MATCH_PD_SEQ_SRC))
> +	$(foreach id, $(MATCH_SPLITS_SEQ), \
> +	  $(SHELL) $(srcdir)/../move-if-change tmp-gimple-isel-match-$(id).cc \
> +	    gimple-isel-match-$(id).cc;)
> +	$(SHELL) $(srcdir)/../move-if-change tmp-gimple-isel-match-auto.h \
> +						gimple-isel-match-auto.h
> +	$(STAMP) s-gimple-isel-match
> +
>  GTFILES = $(CPPLIB_H) $(srcdir)/input.h $(srcdir)/coretypes.h \
>    $(host_xm_file_list) \
>    $(OPTIONS_H_EXTRA) \
> @@ -3216,6 +3240,7 @@ generated_files = config.h tm.h $(TM_P_H) $(TM_D_H) $(TM_JIT_H) $(TM_H) \
>         $(ALL_GTFILES_H) gtype-desc.cc gtype-desc.h version.h \
>         options.h target-hooks-def.h insn-opinit.h \
>         common/common-target-hooks-def.h pass-instances.def \
> +       $(GIMPLE_ISEL_MATCH_PD_SEQ_SRC) \
>         $(GIMPLE_MATCH_PD_SEQ_SRC) $(GENERIC_MATCH_PD_SEQ_SRC) \
>         gimple-match-auto.h generic-match-auto.h \
>         c-family/c-target-hooks-def.h d/d-target-hooks-def.h \
> diff --git a/gcc/gimple-isel-match.pd b/gcc/gimple-isel-match.pd
> new file mode 100644
> index 0000000000000000000000000000000000000000..9e2a2044ba5866389067cfff529b064d1885ea36
> --- /dev/null
> +++ b/gcc/gimple-isel-match.pd
> @@ -0,0 +1,46 @@
> +/* Match-and-simplify patterns for GIMPLE folding during instruction selection.
> +   This file is consumed by genmatch which produces gimple-isel-match.cc.
> +
> +   Copyright (C) 2026 Free Software Foundation, Inc.
> +
> +This file is part of GCC.
> +
> +GCC is free software; you can redistribute it and/or modify it under
> +the terms of the GNU General Public License as published by the Free
> +Software Foundation; either version 3, or (at your option) any later
> +version.
> +
> +GCC is distributed in the hope that it will be useful, but WITHOUT ANY
> +WARRANTY; without even the implied warranty of MERCHANTABILITY or
> +FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
> +for more details.
> +
> +You should have received a copy of the GNU General Public License
> +along with GCC; see the file COPYING3.  If not see
> +<http://www.gnu.org/licenses/>.  */
> +
> +
> +/* Generic tree predicates we inherit.  */
> +(define_predicates
> +   integer_onep integer_zerop integer_all_onesp integer_minus_onep
> +   integer_each_onep integer_truep integer_nonzerop
> +   real_zerop real_onep real_minus_onep
> +   zerop
> +   initializer_each_zero_or_onep
> +   CONSTANT_CLASS_P
> +   poly_int_tree_p
> +   tree_expr_nonnegative_p
> +   tree_expr_nonzero_p
> +   integer_valued_real_p
> +   integer_pow2p
> +   uniform_integer_cst_p
> +   HONOR_NANS
> +   uniform_vector_p
> +   expand_vec_cmp_expr_p
> +   bitmask_inv_cst_vector_p)
> +
> +/* Operator lists.  */
> +(define_operator_list tcc_comparison
> +  lt   le   eq ne ge   gt   unordered ordered   unlt unle ungt unge uneq ltgt)
> +
> +#include "cfn-operators.pd"

We probably want to create a shared header we can include in both
match.pd and here to avoid maintaining this in two places?

> diff --git a/gcc/gimple-isel.cc b/gcc/gimple-isel.cc
> index b193e27b183e1a83d73369b629c81ea0d7db43cd..4348bd53103865c81a9e4c6f2ea434c7ef94f183 100644
> --- a/gcc/gimple-isel.cc
> +++ b/gcc/gimple-isel.cc
> @@ -40,6 +40,10 @@ along with GCC; see the file COPYING3.  If not see
>  #include "gimple-fold.h"
>  #include "internal-fn.h"
>  #include "fold-const.h"
> +#include "gimple-match.h"
> +
> +extern bool gimple_isel_simplify (gimple_match_op *, gimple_seq *,
> +				  tree (*) (tree));
>  
>  /* Expand all ARRAY_REF(VIEW_CONVERT_EXPR) gimple assignments into calls to
>     internal function based on vector type of selected expansion.
> @@ -1360,6 +1364,15 @@ pass_gimple_isel::execute (struct function *fun)
>  	  /* Give the target first try at replacing the instruction.  */
>  	  cfg_changed |= targetm.instruction_selection (fun, &gsi);
>  
> +	  /* Apply gimple-isel-match.pd patterns.  */
> +	  bool stmt_changed = fold_stmt (&gsi, gimple_isel_simplify);

But fold_stmt does a lot more than just apply *.pd patterns, why
not split out the relevant part,

      gimple_seq seq = NULL;
      gimple_match_op res_op;
      if (gimple_simplify (stmt, &res_op, inplace ? NULL : &seq,
                           valueize, valueize)
          && replace_stmt_with_simplification (gsi, &res_op, &seq, inplace,
                                               dce_worklist))
        changed = true;
      else
        gimple_seq_discard (seq);

to a helper and use only that?


> +	  if (stmt_changed && !gsi_end_p (gsi))

I never seen gsi_end_p on a fold result.  It's supposed to be
GIMPLE_NOP if "removed".

> +	    {
> +	      update_stmt (gsi_stmt (gsi));
> +	      if (gimple_code (gsi_stmt (gsi)) == GIMPLE_COND)

Do like forwprop:

                  if (gcond *cond = dyn_cast <gcond *> (stmt))
                    if (gimple_cond_true_p (cond)
                        || gimple_cond_false_p (cond))
                      cfg_changed = true;

> +		cfg_changed = true;
> +	    }
> +
>  	  /* Pre-expand VEC_COND_EXPRs to .VCOND* internal function
>  	     calls mapping to supported optabs.  */
>  	  gimple *g = gimple_expand_vec_cond_expr (&gsi);
> @@ -1400,4 +1413,3 @@ make_pass_gimple_isel (gcc::context *ctxt)
>  {
>    return new pass_gimple_isel (ctxt);
>  }
> -
> 
> 
>
diff mbox series

Patch

diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index fa46ada4980ff8fcbdba696f46e81f59b83dc4b4..09fd733c0b80b5c36546f0c54b6a12cc127003fc 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -228,6 +228,10 @@  GIMPLE_MATCH_PD_SEQ_O = $(patsubst %, gimple-match-%.o, $(MATCH_SPLITS_SEQ))
 GENERIC_MATCH_PD_SEQ_SRC = $(patsubst %, generic-match-%.cc, $(MATCH_SPLITS_SEQ))
 GENERIC_MATCH_PD_SEQ_O = $(patsubst %, generic-match-%.o, $(MATCH_SPLITS_SEQ))
 
+# The number of splits to be made for the gimple-isel-match.pd files.
+GIMPLE_ISEL_MATCH_PD_SEQ_SRC = $(patsubst %, gimple-isel-match-%.cc, $(MATCH_SPLITS_SEQ))
+GIMPLE_ISEL_MATCH_PD_SEQ_O = $(patsubst %, gimple-isel-match-%.o, $(MATCH_SPLITS_SEQ))
+
 # The number of splits to be made for the insn-emit files.
 NUM_INSNEMIT_SPLITS = @DEFAULT_INSNEMIT_PARTITIONS@
 INSNEMIT_SPLITS_SEQ = $(wordlist 1,$(NUM_INSNEMIT_SPLITS),$(one_to_9999))
@@ -1401,6 +1405,7 @@  ANALYZER_OBJS = \
 # the last objects to finish building.
 OBJS = \
 	$(GIMPLE_MATCH_PD_SEQ_O) \
+	$(GIMPLE_ISEL_MATCH_PD_SEQ_O) \
 	gimple-match-exports.o \
 	$(GENERIC_MATCH_PD_SEQ_O) \
 	insn-attrtab.o \
@@ -1987,7 +1992,8 @@  MOSTLYCLEANFILES = insn-flags.h insn-config.h insn-codes.h \
  insn-attr.h insn-attr-common.h insn-attrtab.cc insn-dfatab.cc \
  insn-latencytab.cc insn-opinit.cc insn-opinit.h insn-preds.cc insn-constants.h \
  tm-preds.h tm-constrs.h checksum-options $(GIMPLE_MATCH_PD_SEQ_SRC) \
- $(GENERIC_MATCH_PD_SEQ_SRC) gimple-match-auto.h generic-match-auto.h \
+ $(GIMPLE_ISEL_MATCH_PD_SEQ_SRC) $(GENERIC_MATCH_PD_SEQ_SRC) \
+ gimple-match-auto.h generic-match-auto.h \
  tree-check.h min-insn-modes.cc insn-modes.cc insn-modes.h insn-modes-inline.h \
  genrtl.h gt-*.h gtype-*.h gtype-desc.cc gtyp-input.list \
  case-cfn-macros.h cfn-operators.pd \
@@ -2762,6 +2768,7 @@  $(common_out_object_file): $(common_out_file)
   insn-extract.cc insn-output.cc \
   insn-peep.cc insn-attr.h insn-attr-common.h insn-attrtab.cc \
   insn-dfatab.cc insn-latencytab.cc insn-preds.cc \
+  $(GIMPLE_ISEL_MATCH_PD_SEQ_SRC) \
   $(GIMPLE_MATCH_PD_SEQ_SRC) $(GENERIC_MATCH_PD_SEQ_SRC) \
   gimple-match-auto.h generic-match-auto.h insn-target-def.h
 
@@ -3077,6 +3084,23 @@  s-generic-match: build/genmatch$(build_exeext) \
 						generic-match-auto.h
 	$(STAMP) s-generic-match
 
+# Add gimple-isel-match.pd
+$(GIMPLE_ISEL_MATCH_PD_SEQ_SRC): s-gimple-isel-match gimple-match-head.cc; @true
+gimple-isel-match-auto.h: s-gimple-isel-match; @true
+
+s-gimple-isel-match: build/genmatch$(build_exeext) \
+	    $(srcdir)/gimple-isel-match.pd cfn-operators.pd
+	$(RUN_GEN) build/genmatch$(build_exeext) --gimple \
+	    --header=tmp-gimple-isel-match-auto.h \
+	    --include=gimple-isel-match-auto.h --namespace=isel \
+	    $(srcdir)/gimple-isel-match.pd $(patsubst %, tmp-%, $(GIMPLE_ISEL_MATCH_PD_SEQ_SRC))
+	$(foreach id, $(MATCH_SPLITS_SEQ), \
+	  $(SHELL) $(srcdir)/../move-if-change tmp-gimple-isel-match-$(id).cc \
+	    gimple-isel-match-$(id).cc;)
+	$(SHELL) $(srcdir)/../move-if-change tmp-gimple-isel-match-auto.h \
+						gimple-isel-match-auto.h
+	$(STAMP) s-gimple-isel-match
+
 GTFILES = $(CPPLIB_H) $(srcdir)/input.h $(srcdir)/coretypes.h \
   $(host_xm_file_list) \
   $(OPTIONS_H_EXTRA) \
@@ -3216,6 +3240,7 @@  generated_files = config.h tm.h $(TM_P_H) $(TM_D_H) $(TM_JIT_H) $(TM_H) \
        $(ALL_GTFILES_H) gtype-desc.cc gtype-desc.h version.h \
        options.h target-hooks-def.h insn-opinit.h \
        common/common-target-hooks-def.h pass-instances.def \
+       $(GIMPLE_ISEL_MATCH_PD_SEQ_SRC) \
        $(GIMPLE_MATCH_PD_SEQ_SRC) $(GENERIC_MATCH_PD_SEQ_SRC) \
        gimple-match-auto.h generic-match-auto.h \
        c-family/c-target-hooks-def.h d/d-target-hooks-def.h \
diff --git a/gcc/gimple-isel-match.pd b/gcc/gimple-isel-match.pd
new file mode 100644
index 0000000000000000000000000000000000000000..9e2a2044ba5866389067cfff529b064d1885ea36
--- /dev/null
+++ b/gcc/gimple-isel-match.pd
@@ -0,0 +1,46 @@ 
+/* Match-and-simplify patterns for GIMPLE folding during instruction selection.
+   This file is consumed by genmatch which produces gimple-isel-match.cc.
+
+   Copyright (C) 2026 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+
+/* Generic tree predicates we inherit.  */
+(define_predicates
+   integer_onep integer_zerop integer_all_onesp integer_minus_onep
+   integer_each_onep integer_truep integer_nonzerop
+   real_zerop real_onep real_minus_onep
+   zerop
+   initializer_each_zero_or_onep
+   CONSTANT_CLASS_P
+   poly_int_tree_p
+   tree_expr_nonnegative_p
+   tree_expr_nonzero_p
+   integer_valued_real_p
+   integer_pow2p
+   uniform_integer_cst_p
+   HONOR_NANS
+   uniform_vector_p
+   expand_vec_cmp_expr_p
+   bitmask_inv_cst_vector_p)
+
+/* Operator lists.  */
+(define_operator_list tcc_comparison
+  lt   le   eq ne ge   gt   unordered ordered   unlt unle ungt unge uneq ltgt)
+
+#include "cfn-operators.pd"
diff --git a/gcc/gimple-isel.cc b/gcc/gimple-isel.cc
index b193e27b183e1a83d73369b629c81ea0d7db43cd..4348bd53103865c81a9e4c6f2ea434c7ef94f183 100644
--- a/gcc/gimple-isel.cc
+++ b/gcc/gimple-isel.cc
@@ -40,6 +40,10 @@  along with GCC; see the file COPYING3.  If not see
 #include "gimple-fold.h"
 #include "internal-fn.h"
 #include "fold-const.h"
+#include "gimple-match.h"
+
+extern bool gimple_isel_simplify (gimple_match_op *, gimple_seq *,
+				  tree (*) (tree));
 
 /* Expand all ARRAY_REF(VIEW_CONVERT_EXPR) gimple assignments into calls to
    internal function based on vector type of selected expansion.
@@ -1360,6 +1364,15 @@  pass_gimple_isel::execute (struct function *fun)
 	  /* Give the target first try at replacing the instruction.  */
 	  cfg_changed |= targetm.instruction_selection (fun, &gsi);
 
+	  /* Apply gimple-isel-match.pd patterns.  */
+	  bool stmt_changed = fold_stmt (&gsi, gimple_isel_simplify);
+	  if (stmt_changed && !gsi_end_p (gsi))
+	    {
+	      update_stmt (gsi_stmt (gsi));
+	      if (gimple_code (gsi_stmt (gsi)) == GIMPLE_COND)
+		cfg_changed = true;
+	    }
+
 	  /* Pre-expand VEC_COND_EXPRs to .VCOND* internal function
 	     calls mapping to supported optabs.  */
 	  gimple *g = gimple_expand_vec_cond_expr (&gsi);
@@ -1400,4 +1413,3 @@  make_pass_gimple_isel (gcc::context *ctxt)
 {
   return new pass_gimple_isel (ctxt);
 }
-