PR rtl-optimization/82778

	PR rtl-optimization/82597
	* compare-elim.c (struct comparison): Add in_a_setter field.
	(find_comparison_dom_walker::before_dom_children): Remove killed
	bitmap and df_simulate_find_defs call, instead walk the defs.
	Compute last_setter and initialize in_a_setter.  Merge definitions
	with first initialization for a few variables.
	(try_validate_parallel): Use insn_invalid_p instead of
	recog_memoized.  Return insn rather than just the pattern.
	(try_merge_compare): Fix up comment.  Don't uselessly test if
	in_a is a REG_P.  Use cmp->in_a_setter instead of walking UD
	chains.
	(execute_compare_elim_after_reload): Remove df_chain_add_problem
	call.

	* g++.dg/opt/pr82778.C: New test.

2017-11-01  Michael Collison  <michael.collison@arm.com>

	PR rtl-optimization/82597
	* gcc.dg/pr82597.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@254328 138bc75d-0d04-0410-961f-82ee72b054a4

5 files changed, 165 insertions, 56 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7ef2988ba2d..b903d22ca7d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,25 @@
+2017-11-01  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/82778
+	PR rtl-optimization/82597
+	* compare-elim.c (struct comparison): Add in_a_setter field.
+	(find_comparison_dom_walker::before_dom_children): Remove killed
+	bitmap and df_simulate_find_defs call, instead walk the defs.
+	Compute last_setter and initialize in_a_setter.  Merge definitions
+	with first initialization for a few variables.
+	(try_validate_parallel): Use insn_invalid_p instead of
+	recog_memoized.  Return insn rather than just the pattern.
+	(try_merge_compare): Fix up comment.  Don't uselessly test if
+	in_a is a REG_P.  Use cmp->in_a_setter instead of walking UD
+	chains.
+	(execute_compare_elim_after_reload): Remove df_chain_add_problem
+	call.
+
+2017-11-01  Michael Collison  <michael.collison@arm.com>
+
+	PR rtl-optimization/82597
+	* gcc.dg/pr82597.c: New test.
+
 2017-11-01  Richard Sandiford  <richard.sandiford@linaro.org>
 	    Alan Hayward  <alan.hayward@arm.com>
 	    David Sherwood  <david.sherwood@arm.com>
diff --git a/gcc/compare-elim.c b/gcc/compare-elim.c
index 086fbc76f01..17d08842d15 100644
--- a/gcc/compare-elim.c
+++ b/gcc/compare-elim.c
@@ -97,6 +97,9 @@ struct comparison
   /* The insn prior to the comparison insn that clobbers the flags.  */
   rtx_insn *prev_clobber;
 
+  /* The insn prior to the comparison insn that sets in_a REG.  */
+  rtx_insn *in_a_setter;
+
   /* The two values being compared.  These will be either REGs or
      constants.  */
   rtx in_a, in_b;
@@ -309,26 +312,22 @@ can_eliminate_compare (rtx compare, rtx eh_note, struct comparison *cmp)
 edge
 find_comparison_dom_walker::before_dom_children (basic_block bb)
 {
-  struct comparison *last_cmp;
-  rtx_insn *insn, *next, *last_clobber;
-  bool last_cmp_valid;
+  rtx_insn *insn, *next;
   bool need_purge = false;
-  bitmap killed;
-
-  killed = BITMAP_ALLOC (NULL);
+  rtx_insn *last_setter[FIRST_PSEUDO_REGISTER];
 
   /* The last comparison that was made.  Will be reset to NULL
      once the flags are clobbered.  */
-  last_cmp = NULL;
+  struct comparison *last_cmp = NULL;
 
   /* True iff the last comparison has not been clobbered, nor
      have its inputs.  Used to eliminate duplicate compares.  */
-  last_cmp_valid = false;
+  bool last_cmp_valid = false;
 
   /* The last insn that clobbered the flags, if that insn is of
      a form that may be valid for eliminating a following compare.
      To be reset to NULL once the flags are set otherwise.  */
-  last_clobber = NULL;
+  rtx_insn *last_clobber = NULL;
 
   /* Propagate the last live comparison throughout the extended basic block. */
   if (single_pred_p (bb))
@@ -338,6 +337,7 @@ find_comparison_dom_walker::before_dom_children (basic_block bb)
 	last_cmp_valid = last_cmp->inputs_valid;
     }
 
+  memset (last_setter, 0, sizeof (last_setter));
   for (insn = BB_HEAD (bb); insn; insn = next)
     {
       rtx src;
@@ -346,10 +346,6 @@ find_comparison_dom_walker::before_dom_children (basic_block bb)
       if (!NONDEBUG_INSN_P (insn))
 	continue;
 
-      /* Compute the set of registers modified by this instruction.  */
-      bitmap_clear (killed);
-      df_simulate_find_defs (insn, killed);
-
       src = conforming_compare (insn);
       if (src)
 	{
@@ -373,6 +369,13 @@ find_comparison_dom_walker::before_dom_children (basic_block bb)
 	  last_cmp->in_b = XEXP (src, 1);
 	  last_cmp->eh_note = eh_note;
 	  last_cmp->orig_mode = GET_MODE (src);
+	  if (last_cmp->in_b == const0_rtx
+	      && last_setter[REGNO (last_cmp->in_a)])
+	    {
+	      rtx set = single_set (last_setter[REGNO (last_cmp->in_a)]);
+	      if (set && rtx_equal_p (SET_DEST (set), last_cmp->in_a))
+		last_cmp->in_a_setter = last_setter[REGNO (last_cmp->in_a)];
+	    }
 	  all_compares.safe_push (last_cmp);
 
 	  /* It's unusual, but be prepared for comparison patterns that
@@ -388,28 +391,36 @@ find_comparison_dom_walker::before_dom_children (basic_block bb)
 	    find_flags_uses_in_insn (last_cmp, insn);
 
 	  /* Notice if this instruction kills the flags register.  */
-	  if (bitmap_bit_p (killed, targetm.flags_regnum))
-	    {
-	      /* See if this insn could be the "clobber" that eliminates
-		 a future comparison.   */
-	      last_clobber = (arithmetic_flags_clobber_p (insn) ? insn : NULL);
-
-	      /* In either case, the previous compare is no longer valid.  */
-	      last_cmp = NULL;
-	      last_cmp_valid = false;
-	    }
+	  df_ref def;
+	  FOR_EACH_INSN_DEF (def, insn)
+	    if (DF_REF_REGNO (def) == targetm.flags_regnum)
+	      {
+		/* See if this insn could be the "clobber" that eliminates
+		   a future comparison.   */
+		last_clobber = (arithmetic_flags_clobber_p (insn)
+				? insn : NULL);
+
+		/* In either case, the previous compare is no longer valid.  */
+		last_cmp = NULL;
+		last_cmp_valid = false;
+		break;
+	      }
 	}
 
-      /* Notice if any of the inputs to the comparison have changed.  */
-      if (last_cmp_valid
-	  && (bitmap_bit_p (killed, REGNO (last_cmp->in_a))
-	      || (REG_P (last_cmp->in_b)
-		  && bitmap_bit_p (killed, REGNO (last_cmp->in_b)))))
-	last_cmp_valid = false;
+      /* Notice if any of the inputs to the comparison have changed
+	 and remember last insn that sets each register.  */
+      df_ref def;
+      FOR_EACH_INSN_DEF (def, insn)
+	{
+	  if (last_cmp_valid
+	      && (DF_REF_REGNO (def) == REGNO (last_cmp->in_a)
+		  || (REG_P (last_cmp->in_b)
+		      && DF_REF_REGNO (def) == REGNO (last_cmp->in_b))))
+	    last_cmp_valid = false;
+	  last_setter[DF_REF_REGNO (def)] = insn;
+	}
     }
 
-  BITMAP_FREE (killed);
-
   /* Remember the live comparison for subsequent members of
      the extended basic block.  */
   if (last_cmp)
@@ -625,13 +636,19 @@ can_merge_compare_into_arith (rtx_insn *cmp_insn, rtx_insn *arith_insn)
 static rtx
 try_validate_parallel (rtx set_a, rtx set_b)
 {
-  rtx par
-    = gen_rtx_PARALLEL (VOIDmode, gen_rtvec (2, set_a, set_b));
+  rtx par = gen_rtx_PARALLEL (VOIDmode, gen_rtvec (2, set_a, set_b));
+  rtx_insn *insn = make_insn_raw (par);
 
-  rtx_insn *insn;
-  insn = gen_rtx_INSN (VOIDmode, 0, 0, 0, par, 0, -1, 0);
+  if (insn_invalid_p (insn, false))
+    {
+      crtl->emit.x_cur_insn_uid--;
+      return NULL_RTX;
+    }
 
-  return recog_memoized (insn) > 0 ? par : NULL_RTX;
+  SET_PREV_INSN (insn) = NULL_RTX;
+  SET_NEXT_INSN (insn) = NULL_RTX;
+  INSN_LOCATION (insn) = 0;
+  return insn;
 }
 
 /* For a comparison instruction described by CMP check if it compares a
@@ -643,7 +660,7 @@ try_validate_parallel (rtx set_a, rtx set_b)
    <instructions that don't read the condition register>
    I2: CC := CMP R1 0
    I2 can be merged with I1 into:
-   I1: { R1 := R2 + R3 ; CC := CMP (R2 + R3) 0 }
+   I1: { CC := CMP (R2 + R3) 0 ; R1 := R2 + R3 }
    This catches cases where R1 is used between I1 and I2 and therefore
    combine and other RTL optimisations will not try to propagate it into
    I2.  Return true if we succeeded in merging CMP.  */
@@ -653,7 +670,7 @@ try_merge_compare (struct comparison *cmp)
 {
   rtx_insn *cmp_insn = cmp->insn;
 
-  if (!REG_P (cmp->in_a) || cmp->in_b != const0_rtx)
+  if (cmp->in_b != const0_rtx || cmp->in_a_setter == NULL)
     return false;
   rtx in_a = cmp->in_a;
   df_ref use;
@@ -664,24 +681,8 @@ try_merge_compare (struct comparison *cmp)
   if (!use)
     return false;
 
-  /* Validate the data flow information before attempting to
-     find the instruction that defines in_a.  */
-
-  struct df_link *ref_chain;
-  ref_chain = DF_REF_CHAIN (use);
-  if (!ref_chain || !ref_chain->ref
-      || !DF_REF_INSN_INFO (ref_chain->ref) || ref_chain->next != NULL)
-    return false;
-
-  rtx_insn *def_insn = DF_REF_INSN (ref_chain->ref);
-  /* We found the insn that defines in_a.  Only consider the cases where
-     it is in the same block as the comparison.  */
-  if (BLOCK_FOR_INSN (cmp_insn) != BLOCK_FOR_INSN (def_insn))
-    return false;
-
+  rtx_insn *def_insn = cmp->in_a_setter;
   rtx set = single_set (def_insn);
-  if (!set)
-    return false;
 
   if (!can_merge_compare_into_arith (cmp_insn, def_insn))
     return false;
@@ -855,7 +856,6 @@ try_eliminate_compare (struct comparison *cmp)
 static unsigned int
 execute_compare_elim_after_reload (void)
 {
-  df_chain_add_problem (DF_UD_CHAIN + DF_DU_CHAIN);
   df_analyze ();
 
   gcc_checking_assert (!all_compares.exists ());
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a8143ade842..eba8154804f 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,13 @@
+2017-11-01  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/82778
+	* g++.dg/opt/pr82778.C: New test.
+
+2017-11-01  Michael Collison  <michael.collison@arm.com>
+
+	PR rtl-optimization/82597
+	* gcc.dg/pr82597.c: New test.
+
 2017-11-01  Uros Bizjak  <ubizjak@gmail.com>
 
 	* gcc.target/alpha/sqrt.c: New test.
diff --git a/gcc/testsuite/g++.dg/opt/pr82778.C b/gcc/testsuite/g++.dg/opt/pr82778.C
new file mode 100644
index 00000000000..eeac0c5f38b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/pr82778.C
@@ -0,0 +1,37 @@
+// PR rtl-optimization/82778
+// { dg-do compile }
+// { dg-options "-O2" }
+
+template <typename a, int b> struct c {
+  typedef a d[b];
+  static a e(d f, int g) { return f[g]; }
+};
+template <typename a, int b> struct B {
+  typedef c<a, b> h;
+  typename h::d i;
+  long j;
+  a at() { return h::e(i, j); }
+};
+int k, m, r, s, t;
+char l, n, q;
+short o, p, w;
+struct C {
+  int u;
+};
+B<C, 4> v;
+void x() {
+  if (((p > (q ? v.at().u : k)) >> l - 226) + !(n ^ r * m))
+    s = ((-(((p > (q ? v.at().u : k)) >> l - 226) + !(n ^ r * m)) < 0) /
+             (-(((p > (q ? v.at().u : k)) >> l - 226) + !(n ^ r * m)) ^
+              -25 & o) &&
+         p) >>
+        (0 <= 0
+             ? 0 ||
+                   (-(((p > (q ? v.at().u : k)) >> l - 226) + !(n ^ r * m)) <
+                    0) /
+                       (-(((p > (q ? v.at().u : k)) >> l - 226) +
+                          !(n ^ r * m)) ^ -25 & o)
+             : 0);
+  w = (p > (q ? v.at().u : k)) >> l - 226;
+  t = !(n ^ r * m);
+}
diff --git a/gcc/testsuite/gcc.dg/pr82597.c b/gcc/testsuite/gcc.dg/pr82597.c
new file mode 100644
index 00000000000..98ae264d1c9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr82597.c
@@ -0,0 +1,40 @@
+/* PR rtl-optimization/82597 */
+/* { dg-do compile  }*/
+/* { dg-options "-O2 -funroll-loops" } */
+
+int pb;
+
+void
+ch (unsigned char np, char fc)
+{
+  unsigned char *y6 = &np;
+
+  if (fc != 0)
+    {
+      unsigned char *z1 = &np;
+
+      for (;;)
+        if (*y6 != 0)
+          for (fc = 0; fc < 12; ++fc)
+            {
+              int hh;
+              int tp;
+
+              if (fc != 0)
+                hh = (*z1 != 0) ? fc : 0;
+              else
+                hh = pb;
+
+              tp = fc > 0;
+              if (hh == tp)
+                *y6 = 1;
+            }
+    }
+
+  if (np != 0)
+    y6 = (unsigned char *)&fc;
+  if (pb != 0 && *y6 != 0)
+    for (;;)
+      {
+      }
+}