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* [PATCH 1/2]middle-end: Add new tbranch optab to add support for bit-test-and-branch operations
@ 2022-10-31 11:53 Tamar Christina
  2022-10-31 11:53 ` [PATCH 2/2]AArch64 Support new tbranch optab Tamar Christina
                   ` (2 more replies)
  0 siblings, 3 replies; 33+ messages in thread
From: Tamar Christina @ 2022-10-31 11:53 UTC (permalink / raw)
  To: gcc-patches; +Cc: nd, rguenther, jeffreyalaw

[-- Attachment #1: Type: text/plain, Size: 15179 bytes --]

Hi All,

This adds a new test-and-branch optab that can be used to do a conditional test
of a bit and branch.   This is similar to the cbranch optab but instead can
test any arbitrary bit inside the register.

This patch recognizes boolean comparisons and single bit mask tests.

Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.

Ok for master?

Thanks,
Tamar

gcc/ChangeLog:

	* dojump.cc (do_jump): Pass along value.
	(do_jump_by_parts_greater_rtx): Likewise.
	(do_jump_by_parts_zero_rtx): Likewise.
	(do_jump_by_parts_equality_rtx): Likewise.
	(do_compare_rtx_and_jump): Likewise.
	(do_compare_and_jump): Likewise.
	* dojump.h (do_compare_rtx_and_jump): New.
	* optabs.cc (emit_cmp_and_jump_insn_1): Refactor to take optab to check.
	(validate_test_and_branch): New.
	(emit_cmp_and_jump_insns): Optiobally take a value, and when value is
	supplied then check if it's suitable for tbranch.
	* optabs.def (tbranch$a4): New.
	* doc/md.texi (tbranch@var{mode}4): Document it.
	* optabs.h (emit_cmp_and_jump_insns):
	* tree.h (tree_zero_one_valued_p): New.

--- inline copy of patch -- 
diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index c08691ab4c9a4bfe55ae81e5e228a414d6242d78..f8b32ec12f46d3fb3815f121a16b5a8a1819b66a 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -6972,6 +6972,13 @@ case, you can and should make operand 1's predicate reject some operators
 in the @samp{cstore@var{mode}4} pattern, or remove the pattern altogether
 from the machine description.
 
+@cindex @code{tbranch@var{mode}4} instruction pattern
+@item @samp{tbranch@var{mode}4}
+Conditional branch instruction combined with a bit test-and-compare
+instruction. Operand 0 is a comparison operator.  Operand 1 is the
+operand of the comparison. Operand 2 is the bit position of Operand 1 to test.
+Operand 3 is the @code{code_label} to jump to.
+
 @cindex @code{cbranch@var{mode}4} instruction pattern
 @item @samp{cbranch@var{mode}4}
 Conditional branch instruction combined with a compare instruction.
diff --git a/gcc/dojump.h b/gcc/dojump.h
index e379cceb34bb1765cb575636e4c05b61501fc2cf..d1d79c490c420a805fe48d58740a79c1f25fb839 100644
--- a/gcc/dojump.h
+++ b/gcc/dojump.h
@@ -71,6 +71,10 @@ extern void jumpifnot (tree exp, rtx_code_label *label,
 extern void jumpifnot_1 (enum tree_code, tree, tree, rtx_code_label *,
 			 profile_probability);
 
+extern void do_compare_rtx_and_jump (rtx, rtx, enum rtx_code, int, tree,
+				     machine_mode, rtx, rtx_code_label *,
+				     rtx_code_label *, profile_probability);
+
 extern void do_compare_rtx_and_jump (rtx, rtx, enum rtx_code, int,
 				     machine_mode, rtx, rtx_code_label *,
 				     rtx_code_label *, profile_probability);
diff --git a/gcc/dojump.cc b/gcc/dojump.cc
index 2af0cd1aca3b6af13d5d8799094ee93f18022296..190324f36f1a31990f8c49bc8c0f45c23da5c31e 100644
--- a/gcc/dojump.cc
+++ b/gcc/dojump.cc
@@ -619,7 +619,7 @@ do_jump (tree exp, rtx_code_label *if_false_label,
 	}
       do_compare_rtx_and_jump (temp, CONST0_RTX (GET_MODE (temp)),
 			       NE, TYPE_UNSIGNED (TREE_TYPE (exp)),
-			       GET_MODE (temp), NULL_RTX,
+			       exp, GET_MODE (temp), NULL_RTX,
 			       if_false_label, if_true_label, prob);
     }
 
@@ -687,7 +687,7 @@ do_jump_by_parts_greater_rtx (scalar_int_mode mode, int unsignedp, rtx op0,
 
       /* All but high-order word must be compared as unsigned.  */
       do_compare_rtx_and_jump (op0_word, op1_word, code, (unsignedp || i > 0),
-			       word_mode, NULL_RTX, NULL, if_true_label,
+			       NULL, word_mode, NULL_RTX, NULL, if_true_label,
 			       prob);
 
       /* Emit only one comparison for 0.  Do not emit the last cond jump.  */
@@ -695,8 +695,8 @@ do_jump_by_parts_greater_rtx (scalar_int_mode mode, int unsignedp, rtx op0,
 	break;
 
       /* Consider lower words only if these are equal.  */
-      do_compare_rtx_and_jump (op0_word, op1_word, NE, unsignedp, word_mode,
-			       NULL_RTX, NULL, if_false_label,
+      do_compare_rtx_and_jump (op0_word, op1_word, NE, unsignedp, NULL,
+			       word_mode, NULL_RTX, NULL, if_false_label,
 			       prob.invert ());
     }
 
@@ -755,7 +755,7 @@ do_jump_by_parts_zero_rtx (scalar_int_mode mode, rtx op0,
 
   if (part != 0)
     {
-      do_compare_rtx_and_jump (part, const0_rtx, EQ, 1, word_mode,
+      do_compare_rtx_and_jump (part, const0_rtx, EQ, 1, NULL, word_mode,
 			       NULL_RTX, if_false_label, if_true_label, prob);
       return;
     }
@@ -766,7 +766,7 @@ do_jump_by_parts_zero_rtx (scalar_int_mode mode, rtx op0,
 
   for (i = 0; i < nwords; i++)
     do_compare_rtx_and_jump (operand_subword_force (op0, i, mode),
-                             const0_rtx, EQ, 1, word_mode, NULL_RTX,
+			     const0_rtx, EQ, 1, NULL, word_mode, NULL_RTX,
 			     if_false_label, NULL, prob);
 
   if (if_true_label)
@@ -809,8 +809,8 @@ do_jump_by_parts_equality_rtx (scalar_int_mode mode, rtx op0, rtx op1,
 
   for (i = 0; i < nwords; i++)
     do_compare_rtx_and_jump (operand_subword_force (op0, i, mode),
-                             operand_subword_force (op1, i, mode),
-                             EQ, 0, word_mode, NULL_RTX,
+			     operand_subword_force (op1, i, mode),
+			     EQ, 0, NULL, word_mode, NULL_RTX,
 			     if_false_label, NULL, prob);
 
   if (if_true_label)
@@ -962,6 +962,23 @@ do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
 			 rtx_code_label *if_false_label,
 			 rtx_code_label *if_true_label,
 			 profile_probability prob)
+{
+  do_compare_rtx_and_jump (op0, op1, code, unsignedp, NULL, mode, size,
+			  if_false_label, if_true_label, prob);
+}
+
+/* Like do_compare_and_jump but expects the values to compare as two rtx's.
+   The decision as to signed or unsigned comparison must be made by the caller.
+
+   If MODE is BLKmode, SIZE is an RTX giving the size of the objects being
+   compared.  */
+
+void
+do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
+			 tree val, machine_mode mode, rtx size,
+			 rtx_code_label *if_false_label,
+			 rtx_code_label *if_true_label,
+			 profile_probability prob)
 {
   rtx tem;
   rtx_code_label *dummy_label = NULL;
@@ -1177,8 +1194,10 @@ do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
 		    }
 		  else
 		    dest_label = if_false_label;
-                  do_compare_rtx_and_jump (op0, op1, first_code, unsignedp, mode,
-					   size, dest_label, NULL, first_prob);
+
+		  do_compare_rtx_and_jump (op0, op1, first_code, unsignedp,
+					   val, mode, size, dest_label, NULL,
+					   first_prob);
 		}
 	      /* For !and_them we want to split:
 		 if (x) goto t; // prob;
@@ -1192,8 +1211,9 @@ do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
               else
 		{
 		  profile_probability first_prob = prob.split (cprob);
-		  do_compare_rtx_and_jump (op0, op1, first_code, unsignedp, mode,
-					   size, NULL, if_true_label, first_prob);
+		  do_compare_rtx_and_jump (op0, op1, first_code, unsignedp,
+					   val, mode, size, NULL,
+					   if_true_label, first_prob);
 		  if (orig_code == NE && can_compare_p (UNEQ, mode, ccp_jump))
 		    {
 		      /* x != y can be split into x unord y || x ltgt y
@@ -1215,7 +1235,7 @@ do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
 	    }
 	}
 
-      emit_cmp_and_jump_insns (op0, op1, code, size, mode, unsignedp,
+      emit_cmp_and_jump_insns (op0, op1, code, size, mode, unsignedp, val,
 			       if_true_label, prob);
     }
 
@@ -1289,9 +1309,9 @@ do_compare_and_jump (tree treeop0, tree treeop1, enum rtx_code signed_code,
       op1 = new_op1;
     }
 
-  do_compare_rtx_and_jump (op0, op1, code, unsignedp, mode,
-                           ((mode == BLKmode)
-                            ? expr_size (treeop0) : NULL_RTX),
+  do_compare_rtx_and_jump (op0, op1, code, unsignedp, treeop0, mode,
+			   ((mode == BLKmode)
+			    ? expr_size (treeop0) : NULL_RTX),
 			   if_false_label, if_true_label, prob);
 }
 
diff --git a/gcc/optabs.cc b/gcc/optabs.cc
index cff37ccb0dfc3dd79b97d0abfd872f340855dc96..5b368f77e91d3fce29870f1a5b54a0301e6b7794 100644
--- a/gcc/optabs.cc
+++ b/gcc/optabs.cc
@@ -46,6 +46,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "libfuncs.h"
 #include "internal-fn.h"
 #include "langhooks.h"
+#include "gimple.h"
 
 static void prepare_float_lib_cmp (rtx, rtx, enum rtx_code, rtx *,
 				   machine_mode *);
@@ -4620,7 +4621,7 @@ prepare_operand (enum insn_code icode, rtx x, int opnum, machine_mode mode,
 
 static void
 emit_cmp_and_jump_insn_1 (rtx test, machine_mode mode, rtx label,
-			  profile_probability prob)
+			  direct_optab cmp_optab, profile_probability prob)
 {
   machine_mode optab_mode;
   enum mode_class mclass;
@@ -4629,7 +4630,7 @@ emit_cmp_and_jump_insn_1 (rtx test, machine_mode mode, rtx label,
 
   mclass = GET_MODE_CLASS (mode);
   optab_mode = (mclass == MODE_CC) ? CCmode : mode;
-  icode = optab_handler (cbranch_optab, optab_mode);
+  icode = optab_handler (cmp_optab, optab_mode);
 
   gcc_assert (icode != CODE_FOR_nothing);
   gcc_assert (insn_operand_matches (icode, 0, test));
@@ -4644,6 +4645,71 @@ emit_cmp_and_jump_insn_1 (rtx test, machine_mode mode, rtx label,
     add_reg_br_prob_note (insn, prob);
 }
 
+/* Check to see if the supplied comparison in PTEST can be performed as a
+   bit-test-and-branch instead.  VAL must contain the original tree
+   expression of the non-zero operand which will be used to rewrite the
+   comparison in PTEST.
+
+   Returns TRUE if operation succeeds and returns updated PMODE and PTEST,
+   else FALSE.  */
+
+bool
+static validate_test_and_branch (tree val, rtx *ptest, machine_mode *pmode)
+{
+  if (!val)
+    return false;
+
+  machine_mode mode = TYPE_MODE (TREE_TYPE (val));
+  rtx test = *ptest;
+
+  if (GET_CODE (test) != EQ && GET_CODE (test) != NE)
+    return false;
+
+  if (tree_zero_one_valued_p (val))
+    {
+      auto pos = BYTES_BIG_ENDIAN ? GET_MODE_BITSIZE (mode) - 1 : 0;
+      XEXP (test, 1) = gen_int_mode (pos, mode);
+      *ptest = test;
+      *pmode = mode;
+      return true;
+    }
+
+  if (TREE_CODE (val) != SSA_NAME)
+    return false;
+
+  gimple *def = SSA_NAME_DEF_STMT (val);
+  if (!is_gimple_assign (def)
+      || gimple_assign_rhs_code (def) != BIT_AND_EXPR)
+    return false;
+
+  tree cst = gimple_assign_rhs2 (def);
+
+  if (!tree_fits_uhwi_p (cst))
+    return false;
+
+  tree op0 = gimple_assign_rhs1 (def);
+  if (TREE_CODE (op0) == SSA_NAME)
+    {
+      def = SSA_NAME_DEF_STMT (op0);
+      if (gimple_assign_cast_p (def))
+	op0 = gimple_assign_rhs1 (def);
+    }
+
+  wide_int wcst = wi::uhwi (tree_to_uhwi (cst),
+			    TYPE_PRECISION (TREE_TYPE (op0)));
+  int bitpos;
+
+  if ((bitpos = wi::exact_log2 (wcst)) == -1)
+    return false;
+
+  mode = TYPE_MODE (TREE_TYPE (op0));
+  auto pos = BYTES_BIG_ENDIAN ? GET_MODE_BITSIZE (mode) - 1 - bitpos : bitpos;
+  XEXP (test, 1) = gen_int_mode (pos, mode);
+  *ptest = test;
+  *pmode = mode;
+  return true;
+}
+
 /* Generate code to compare X with Y so that the condition codes are
    set and to jump to LABEL if the condition is true.  If X is a
    constant and Y is not a constant, then the comparison is swapped to
@@ -4661,15 +4727,18 @@ emit_cmp_and_jump_insn_1 (rtx test, machine_mode mode, rtx label,
    It will be potentially converted into an unsigned variant based on
    UNSIGNEDP to select a proper jump instruction.
    
-   PROB is the probability of jumping to LABEL.  */
+   PROB is the probability of jumping to LABEL.  If the comparison is against
+   zero then VAL contains the expression from which the non-zero RTL is
+   derived.  */
 
 void
 emit_cmp_and_jump_insns (rtx x, rtx y, enum rtx_code comparison, rtx size,
-			 machine_mode mode, int unsignedp, rtx label,
+			 machine_mode mode, int unsignedp, tree val, rtx label,
                          profile_probability prob)
 {
   rtx op0 = x, op1 = y;
   rtx test;
+  enum insn_code icode;
 
   /* Swap operands and condition to ensure canonical RTL.  */
   if (swap_commutative_operands_p (x, y)
@@ -4690,10 +4759,37 @@ emit_cmp_and_jump_insns (rtx x, rtx y, enum rtx_code comparison, rtx size,
 
   prepare_cmp_insn (op0, op1, comparison, size, unsignedp, OPTAB_LIB_WIDEN,
 		    &test, &mode);
-  emit_cmp_and_jump_insn_1 (test, mode, label, prob);
+
+  /* Check if we're comparing a truth type with 0, and if so check if
+     the target supports tbranch.  */
+  machine_mode tmode = mode;
+  if (op1 == CONST0_RTX (GET_MODE (op1))
+      && validate_test_and_branch (val, &test, &tmode))
+    {
+      /* If the target supports the testbit comparison directly, great.  */
+      icode = direct_optab_handler (tbranch_optab, tmode);
+      if (icode != CODE_FOR_nothing)
+	{
+	  emit_cmp_and_jump_insn_1 (test, tmode, label, tbranch_optab, prob);
+	  return;
+	}
+    }
+
+  emit_cmp_and_jump_insn_1 (test, mode, label, cbranch_optab, prob);
 }
 
-\f
+/* Overloaded version of emit_cmp_and_jump_insns in which VAL is unknown.  */
+
+void
+emit_cmp_and_jump_insns (rtx x, rtx y, enum rtx_code comparison, rtx size,
+			 machine_mode mode, int unsignedp, rtx label,
+			 profile_probability prob)
+{
+  emit_cmp_and_jump_insns (x, y, comparison, size, mode, unsignedp, NULL,
+			   label, prob);
+}
+
+
 /* Emit a library call comparison between floating point X and Y.
    COMPARISON is the rtl operator to compare with (EQ, NE, GT, etc.).  */
 
diff --git a/gcc/optabs.def b/gcc/optabs.def
index 9947aed67fb8a3b675cb0aab9aeb059f89644106..623a596aca2f538a03602e02e6ac12f43f3303c4 100644
--- a/gcc/optabs.def
+++ b/gcc/optabs.def
@@ -220,6 +220,7 @@ OPTAB_D (reload_in_optab, "reload_in$a")
 OPTAB_D (reload_out_optab, "reload_out$a")
 
 OPTAB_DC(cbranch_optab, "cbranch$a4", COMPARE)
+OPTAB_D (tbranch_optab, "tbranch$a4")
 OPTAB_D (addcc_optab, "add$acc")
 OPTAB_D (negcc_optab, "neg$acc")
 OPTAB_D (notcc_optab, "not$acc")
diff --git a/gcc/optabs.h b/gcc/optabs.h
index cfd7c742d2d21b0539f5227c22a94f32c793d6f7..cd55604bc3d452d7e28c5530bb4793d481766f4f 100644
--- a/gcc/optabs.h
+++ b/gcc/optabs.h
@@ -268,6 +268,10 @@ extern void emit_cmp_and_jump_insns (rtx, rtx, enum rtx_code, rtx,
 				     machine_mode, int, rtx,
 				     profile_probability prob
 					= profile_probability::uninitialized ());
+extern void emit_cmp_and_jump_insns (rtx, rtx, enum rtx_code, rtx,
+				     machine_mode, int, tree, rtx,
+				     profile_probability prob
+					= profile_probability::uninitialized ());
 
 /* Generate code to indirectly jump to a location given in the rtx LOC.  */
 extern void emit_indirect_jump (rtx);
diff --git a/gcc/tree.h b/gcc/tree.h
index 8f8a9660c9e0605eb516de194640b8c1b531b798..be3d2dee82f692e81082cf21c878c10f9fe9e1f1 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -4690,6 +4690,7 @@ extern tree signed_or_unsigned_type_for (int, tree);
 extern tree signed_type_for (tree);
 extern tree unsigned_type_for (tree);
 extern bool is_truth_type_for (tree, tree);
+extern bool tree_zero_one_valued_p (tree);
 extern tree truth_type_for (tree);
 extern tree build_pointer_type_for_mode (tree, machine_mode, bool);
 extern tree build_pointer_type (tree);




-- 

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diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index c08691ab4c9a4bfe55ae81e5e228a414d6242d78..f8b32ec12f46d3fb3815f121a16b5a8a1819b66a 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -6972,6 +6972,13 @@ case, you can and should make operand 1's predicate reject some operators
 in the @samp{cstore@var{mode}4} pattern, or remove the pattern altogether
 from the machine description.
 
+@cindex @code{tbranch@var{mode}4} instruction pattern
+@item @samp{tbranch@var{mode}4}
+Conditional branch instruction combined with a bit test-and-compare
+instruction. Operand 0 is a comparison operator.  Operand 1 is the
+operand of the comparison. Operand 2 is the bit position of Operand 1 to test.
+Operand 3 is the @code{code_label} to jump to.
+
 @cindex @code{cbranch@var{mode}4} instruction pattern
 @item @samp{cbranch@var{mode}4}
 Conditional branch instruction combined with a compare instruction.
diff --git a/gcc/dojump.h b/gcc/dojump.h
index e379cceb34bb1765cb575636e4c05b61501fc2cf..d1d79c490c420a805fe48d58740a79c1f25fb839 100644
--- a/gcc/dojump.h
+++ b/gcc/dojump.h
@@ -71,6 +71,10 @@ extern void jumpifnot (tree exp, rtx_code_label *label,
 extern void jumpifnot_1 (enum tree_code, tree, tree, rtx_code_label *,
 			 profile_probability);
 
+extern void do_compare_rtx_and_jump (rtx, rtx, enum rtx_code, int, tree,
+				     machine_mode, rtx, rtx_code_label *,
+				     rtx_code_label *, profile_probability);
+
 extern void do_compare_rtx_and_jump (rtx, rtx, enum rtx_code, int,
 				     machine_mode, rtx, rtx_code_label *,
 				     rtx_code_label *, profile_probability);
diff --git a/gcc/dojump.cc b/gcc/dojump.cc
index 2af0cd1aca3b6af13d5d8799094ee93f18022296..190324f36f1a31990f8c49bc8c0f45c23da5c31e 100644
--- a/gcc/dojump.cc
+++ b/gcc/dojump.cc
@@ -619,7 +619,7 @@ do_jump (tree exp, rtx_code_label *if_false_label,
 	}
       do_compare_rtx_and_jump (temp, CONST0_RTX (GET_MODE (temp)),
 			       NE, TYPE_UNSIGNED (TREE_TYPE (exp)),
-			       GET_MODE (temp), NULL_RTX,
+			       exp, GET_MODE (temp), NULL_RTX,
 			       if_false_label, if_true_label, prob);
     }
 
@@ -687,7 +687,7 @@ do_jump_by_parts_greater_rtx (scalar_int_mode mode, int unsignedp, rtx op0,
 
       /* All but high-order word must be compared as unsigned.  */
       do_compare_rtx_and_jump (op0_word, op1_word, code, (unsignedp || i > 0),
-			       word_mode, NULL_RTX, NULL, if_true_label,
+			       NULL, word_mode, NULL_RTX, NULL, if_true_label,
 			       prob);
 
       /* Emit only one comparison for 0.  Do not emit the last cond jump.  */
@@ -695,8 +695,8 @@ do_jump_by_parts_greater_rtx (scalar_int_mode mode, int unsignedp, rtx op0,
 	break;
 
       /* Consider lower words only if these are equal.  */
-      do_compare_rtx_and_jump (op0_word, op1_word, NE, unsignedp, word_mode,
-			       NULL_RTX, NULL, if_false_label,
+      do_compare_rtx_and_jump (op0_word, op1_word, NE, unsignedp, NULL,
+			       word_mode, NULL_RTX, NULL, if_false_label,
 			       prob.invert ());
     }
 
@@ -755,7 +755,7 @@ do_jump_by_parts_zero_rtx (scalar_int_mode mode, rtx op0,
 
   if (part != 0)
     {
-      do_compare_rtx_and_jump (part, const0_rtx, EQ, 1, word_mode,
+      do_compare_rtx_and_jump (part, const0_rtx, EQ, 1, NULL, word_mode,
 			       NULL_RTX, if_false_label, if_true_label, prob);
       return;
     }
@@ -766,7 +766,7 @@ do_jump_by_parts_zero_rtx (scalar_int_mode mode, rtx op0,
 
   for (i = 0; i < nwords; i++)
     do_compare_rtx_and_jump (operand_subword_force (op0, i, mode),
-                             const0_rtx, EQ, 1, word_mode, NULL_RTX,
+			     const0_rtx, EQ, 1, NULL, word_mode, NULL_RTX,
 			     if_false_label, NULL, prob);
 
   if (if_true_label)
@@ -809,8 +809,8 @@ do_jump_by_parts_equality_rtx (scalar_int_mode mode, rtx op0, rtx op1,
 
   for (i = 0; i < nwords; i++)
     do_compare_rtx_and_jump (operand_subword_force (op0, i, mode),
-                             operand_subword_force (op1, i, mode),
-                             EQ, 0, word_mode, NULL_RTX,
+			     operand_subword_force (op1, i, mode),
+			     EQ, 0, NULL, word_mode, NULL_RTX,
 			     if_false_label, NULL, prob);
 
   if (if_true_label)
@@ -962,6 +962,23 @@ do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
 			 rtx_code_label *if_false_label,
 			 rtx_code_label *if_true_label,
 			 profile_probability prob)
+{
+  do_compare_rtx_and_jump (op0, op1, code, unsignedp, NULL, mode, size,
+			  if_false_label, if_true_label, prob);
+}
+
+/* Like do_compare_and_jump but expects the values to compare as two rtx's.
+   The decision as to signed or unsigned comparison must be made by the caller.
+
+   If MODE is BLKmode, SIZE is an RTX giving the size of the objects being
+   compared.  */
+
+void
+do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
+			 tree val, machine_mode mode, rtx size,
+			 rtx_code_label *if_false_label,
+			 rtx_code_label *if_true_label,
+			 profile_probability prob)
 {
   rtx tem;
   rtx_code_label *dummy_label = NULL;
@@ -1177,8 +1194,10 @@ do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
 		    }
 		  else
 		    dest_label = if_false_label;
-                  do_compare_rtx_and_jump (op0, op1, first_code, unsignedp, mode,
-					   size, dest_label, NULL, first_prob);
+
+		  do_compare_rtx_and_jump (op0, op1, first_code, unsignedp,
+					   val, mode, size, dest_label, NULL,
+					   first_prob);
 		}
 	      /* For !and_them we want to split:
 		 if (x) goto t; // prob;
@@ -1192,8 +1211,9 @@ do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
               else
 		{
 		  profile_probability first_prob = prob.split (cprob);
-		  do_compare_rtx_and_jump (op0, op1, first_code, unsignedp, mode,
-					   size, NULL, if_true_label, first_prob);
+		  do_compare_rtx_and_jump (op0, op1, first_code, unsignedp,
+					   val, mode, size, NULL,
+					   if_true_label, first_prob);
 		  if (orig_code == NE && can_compare_p (UNEQ, mode, ccp_jump))
 		    {
 		      /* x != y can be split into x unord y || x ltgt y
@@ -1215,7 +1235,7 @@ do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
 	    }
 	}
 
-      emit_cmp_and_jump_insns (op0, op1, code, size, mode, unsignedp,
+      emit_cmp_and_jump_insns (op0, op1, code, size, mode, unsignedp, val,
 			       if_true_label, prob);
     }
 
@@ -1289,9 +1309,9 @@ do_compare_and_jump (tree treeop0, tree treeop1, enum rtx_code signed_code,
       op1 = new_op1;
     }
 
-  do_compare_rtx_and_jump (op0, op1, code, unsignedp, mode,
-                           ((mode == BLKmode)
-                            ? expr_size (treeop0) : NULL_RTX),
+  do_compare_rtx_and_jump (op0, op1, code, unsignedp, treeop0, mode,
+			   ((mode == BLKmode)
+			    ? expr_size (treeop0) : NULL_RTX),
 			   if_false_label, if_true_label, prob);
 }
 
diff --git a/gcc/optabs.cc b/gcc/optabs.cc
index cff37ccb0dfc3dd79b97d0abfd872f340855dc96..5b368f77e91d3fce29870f1a5b54a0301e6b7794 100644
--- a/gcc/optabs.cc
+++ b/gcc/optabs.cc
@@ -46,6 +46,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "libfuncs.h"
 #include "internal-fn.h"
 #include "langhooks.h"
+#include "gimple.h"
 
 static void prepare_float_lib_cmp (rtx, rtx, enum rtx_code, rtx *,
 				   machine_mode *);
@@ -4620,7 +4621,7 @@ prepare_operand (enum insn_code icode, rtx x, int opnum, machine_mode mode,
 
 static void
 emit_cmp_and_jump_insn_1 (rtx test, machine_mode mode, rtx label,
-			  profile_probability prob)
+			  direct_optab cmp_optab, profile_probability prob)
 {
   machine_mode optab_mode;
   enum mode_class mclass;
@@ -4629,7 +4630,7 @@ emit_cmp_and_jump_insn_1 (rtx test, machine_mode mode, rtx label,
 
   mclass = GET_MODE_CLASS (mode);
   optab_mode = (mclass == MODE_CC) ? CCmode : mode;
-  icode = optab_handler (cbranch_optab, optab_mode);
+  icode = optab_handler (cmp_optab, optab_mode);
 
   gcc_assert (icode != CODE_FOR_nothing);
   gcc_assert (insn_operand_matches (icode, 0, test));
@@ -4644,6 +4645,71 @@ emit_cmp_and_jump_insn_1 (rtx test, machine_mode mode, rtx label,
     add_reg_br_prob_note (insn, prob);
 }
 
+/* Check to see if the supplied comparison in PTEST can be performed as a
+   bit-test-and-branch instead.  VAL must contain the original tree
+   expression of the non-zero operand which will be used to rewrite the
+   comparison in PTEST.
+
+   Returns TRUE if operation succeeds and returns updated PMODE and PTEST,
+   else FALSE.  */
+
+bool
+static validate_test_and_branch (tree val, rtx *ptest, machine_mode *pmode)
+{
+  if (!val)
+    return false;
+
+  machine_mode mode = TYPE_MODE (TREE_TYPE (val));
+  rtx test = *ptest;
+
+  if (GET_CODE (test) != EQ && GET_CODE (test) != NE)
+    return false;
+
+  if (tree_zero_one_valued_p (val))
+    {
+      auto pos = BYTES_BIG_ENDIAN ? GET_MODE_BITSIZE (mode) - 1 : 0;
+      XEXP (test, 1) = gen_int_mode (pos, mode);
+      *ptest = test;
+      *pmode = mode;
+      return true;
+    }
+
+  if (TREE_CODE (val) != SSA_NAME)
+    return false;
+
+  gimple *def = SSA_NAME_DEF_STMT (val);
+  if (!is_gimple_assign (def)
+      || gimple_assign_rhs_code (def) != BIT_AND_EXPR)
+    return false;
+
+  tree cst = gimple_assign_rhs2 (def);
+
+  if (!tree_fits_uhwi_p (cst))
+    return false;
+
+  tree op0 = gimple_assign_rhs1 (def);
+  if (TREE_CODE (op0) == SSA_NAME)
+    {
+      def = SSA_NAME_DEF_STMT (op0);
+      if (gimple_assign_cast_p (def))
+	op0 = gimple_assign_rhs1 (def);
+    }
+
+  wide_int wcst = wi::uhwi (tree_to_uhwi (cst),
+			    TYPE_PRECISION (TREE_TYPE (op0)));
+  int bitpos;
+
+  if ((bitpos = wi::exact_log2 (wcst)) == -1)
+    return false;
+
+  mode = TYPE_MODE (TREE_TYPE (op0));
+  auto pos = BYTES_BIG_ENDIAN ? GET_MODE_BITSIZE (mode) - 1 - bitpos : bitpos;
+  XEXP (test, 1) = gen_int_mode (pos, mode);
+  *ptest = test;
+  *pmode = mode;
+  return true;
+}
+
 /* Generate code to compare X with Y so that the condition codes are
    set and to jump to LABEL if the condition is true.  If X is a
    constant and Y is not a constant, then the comparison is swapped to
@@ -4661,15 +4727,18 @@ emit_cmp_and_jump_insn_1 (rtx test, machine_mode mode, rtx label,
    It will be potentially converted into an unsigned variant based on
    UNSIGNEDP to select a proper jump instruction.
    
-   PROB is the probability of jumping to LABEL.  */
+   PROB is the probability of jumping to LABEL.  If the comparison is against
+   zero then VAL contains the expression from which the non-zero RTL is
+   derived.  */
 
 void
 emit_cmp_and_jump_insns (rtx x, rtx y, enum rtx_code comparison, rtx size,
-			 machine_mode mode, int unsignedp, rtx label,
+			 machine_mode mode, int unsignedp, tree val, rtx label,
                          profile_probability prob)
 {
   rtx op0 = x, op1 = y;
   rtx test;
+  enum insn_code icode;
 
   /* Swap operands and condition to ensure canonical RTL.  */
   if (swap_commutative_operands_p (x, y)
@@ -4690,10 +4759,37 @@ emit_cmp_and_jump_insns (rtx x, rtx y, enum rtx_code comparison, rtx size,
 
   prepare_cmp_insn (op0, op1, comparison, size, unsignedp, OPTAB_LIB_WIDEN,
 		    &test, &mode);
-  emit_cmp_and_jump_insn_1 (test, mode, label, prob);
+
+  /* Check if we're comparing a truth type with 0, and if so check if
+     the target supports tbranch.  */
+  machine_mode tmode = mode;
+  if (op1 == CONST0_RTX (GET_MODE (op1))
+      && validate_test_and_branch (val, &test, &tmode))
+    {
+      /* If the target supports the testbit comparison directly, great.  */
+      icode = direct_optab_handler (tbranch_optab, tmode);
+      if (icode != CODE_FOR_nothing)
+	{
+	  emit_cmp_and_jump_insn_1 (test, tmode, label, tbranch_optab, prob);
+	  return;
+	}
+    }
+
+  emit_cmp_and_jump_insn_1 (test, mode, label, cbranch_optab, prob);
 }
 
-\f
+/* Overloaded version of emit_cmp_and_jump_insns in which VAL is unknown.  */
+
+void
+emit_cmp_and_jump_insns (rtx x, rtx y, enum rtx_code comparison, rtx size,
+			 machine_mode mode, int unsignedp, rtx label,
+			 profile_probability prob)
+{
+  emit_cmp_and_jump_insns (x, y, comparison, size, mode, unsignedp, NULL,
+			   label, prob);
+}
+
+
 /* Emit a library call comparison between floating point X and Y.
    COMPARISON is the rtl operator to compare with (EQ, NE, GT, etc.).  */
 
diff --git a/gcc/optabs.def b/gcc/optabs.def
index 9947aed67fb8a3b675cb0aab9aeb059f89644106..623a596aca2f538a03602e02e6ac12f43f3303c4 100644
--- a/gcc/optabs.def
+++ b/gcc/optabs.def
@@ -220,6 +220,7 @@ OPTAB_D (reload_in_optab, "reload_in$a")
 OPTAB_D (reload_out_optab, "reload_out$a")
 
 OPTAB_DC(cbranch_optab, "cbranch$a4", COMPARE)
+OPTAB_D (tbranch_optab, "tbranch$a4")
 OPTAB_D (addcc_optab, "add$acc")
 OPTAB_D (negcc_optab, "neg$acc")
 OPTAB_D (notcc_optab, "not$acc")
diff --git a/gcc/optabs.h b/gcc/optabs.h
index cfd7c742d2d21b0539f5227c22a94f32c793d6f7..cd55604bc3d452d7e28c5530bb4793d481766f4f 100644
--- a/gcc/optabs.h
+++ b/gcc/optabs.h
@@ -268,6 +268,10 @@ extern void emit_cmp_and_jump_insns (rtx, rtx, enum rtx_code, rtx,
 				     machine_mode, int, rtx,
 				     profile_probability prob
 					= profile_probability::uninitialized ());
+extern void emit_cmp_and_jump_insns (rtx, rtx, enum rtx_code, rtx,
+				     machine_mode, int, tree, rtx,
+				     profile_probability prob
+					= profile_probability::uninitialized ());
 
 /* Generate code to indirectly jump to a location given in the rtx LOC.  */
 extern void emit_indirect_jump (rtx);
diff --git a/gcc/tree.h b/gcc/tree.h
index 8f8a9660c9e0605eb516de194640b8c1b531b798..be3d2dee82f692e81082cf21c878c10f9fe9e1f1 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -4690,6 +4690,7 @@ extern tree signed_or_unsigned_type_for (int, tree);
 extern tree signed_type_for (tree);
 extern tree unsigned_type_for (tree);
 extern bool is_truth_type_for (tree, tree);
+extern bool tree_zero_one_valued_p (tree);
 extern tree truth_type_for (tree);
 extern tree build_pointer_type_for_mode (tree, machine_mode, bool);
 extern tree build_pointer_type (tree);




^ permalink raw reply	[flat|nested] 33+ messages in thread
end of thread, other threads:[~2022-12-05 14:06 UTC | newest]

Thread overview: 33+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-10-31 11:53 [PATCH 1/2]middle-end: Add new tbranch optab to add support for bit-test-and-branch operations Tamar Christina
2022-10-31 11:53 ` [PATCH 2/2]AArch64 Support new tbranch optab Tamar Christina
2022-11-14 15:58   ` Tamar Christina
2022-11-15 10:36     ` Richard Sandiford
2022-11-15 10:42       ` Tamar Christina
2022-11-15 10:50         ` Richard Sandiford
2022-11-15 11:00           ` Tamar Christina
2022-11-15 11:14             ` Richard Sandiford
2022-11-15 11:23               ` Tamar Christina
2022-11-15 11:33                 ` Richard Sandiford
2022-11-15 11:39                   ` Tamar Christina
2022-11-22 13:48                   ` Tamar Christina
2022-11-22 14:00                     ` Richard Sandiford
2022-11-24 12:18                       ` Tamar Christina
2022-12-01 16:44                         ` Tamar Christina
2022-12-05 14:06                           ` Richard Sandiford
2022-10-31 11:54 ` [PATCH]AArch64 Extend umov and sbfx patterns Tamar Christina
2022-10-31 12:26   ` Richard Sandiford
2022-11-11 14:42     ` Tamar Christina
2022-11-15 11:10       ` Richard Sandiford
2022-10-31 21:16 ` [PATCH 1/2]middle-end: Add new tbranch optab to add support for bit-test-and-branch operations Jeff Law
2022-11-01 15:53   ` Tamar Christina
2022-11-01 17:00     ` Jeff Law
2022-11-02  9:55       ` Tamar Christina
2022-11-02 11:08         ` Aldy Hernandez
2022-11-05 14:23           ` Richard Biener
2022-11-14 15:56             ` Tamar Christina
2022-11-14 16:22               ` Jeff Law
2022-11-15  7:33               ` Richard Biener
2022-12-01 16:29                 ` Tamar Christina
2022-12-02  7:09                   ` Richard Biener
2022-12-05 12:00                   ` Richard Sandiford
2022-12-05 13:14                     ` Richard Sandiford

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