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* [PATCH] Fix PR tree-optimization/71077
@ 2016-05-31  8:15 Patrick Palka
  2016-05-31 10:28 ` Richard Biener
  0 siblings, 1 reply; 2+ messages in thread
From: Patrick Palka @ 2016-05-31  8:15 UTC (permalink / raw)
  To: gcc-patches; +Cc: Patrick Palka

In this PR the function simplify_control_stmt_condition_1(), which is
responsible for recursing into the operands of a GIMPLE_COND during jump
threading to check for dominating ASSERT_EXPRs, was erroneously
returning a VECTOR_CST when it should instead be returning an
INTEGER_CST.  The problem is that the zero/one constants that this
function uses share the type of the GIMPLE_COND's operands, operands
which may be vectors.  This makes no sense and there is no reason to
build and use such constants instead of using boolean_[true|false]_node
since all that matters is whether a constant returned by
simplify_control_stmt_condition() correctly satisfies
integer_[zero|one]p.  So this patch makes the combining part of
simplify_control_stmt_condition_1() just use boolean_false_node or
boolean_true_node as the designated false/true values.

Does this look OK to commit after bootstrap+regtest on
x86_64-pc-linux-gnu?  (I'm not sure if I put the test in the proper
directory since no other test in tree-ssa uses -flto.  Also not sure if
an i686 target accepts the -march=core-avx2 flag.)

gcc/ChangeLog:

	PR tree-optimization/71077
	* tree-ssa-threadedge.c (simplify_control_stmt_condition_1): In
	the combining step, use boolean_false_node and boolean_true_node
	as the designated false/true return values.

gcc/testsuite/ChangeLog:

	PR tree-optimization/71077
	* gcc.dg/tree-ssa/pr71077.c: New test.
---
 gcc/testsuite/gcc.dg/tree-ssa/pr71077.c | 18 ++++++++++++++++++
 gcc/tree-ssa-threadedge.c               | 26 ++++++++++++--------------
 2 files changed, 30 insertions(+), 14 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr71077.c

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr71077.c b/gcc/testsuite/gcc.dg/tree-ssa/pr71077.c
new file mode 100644
index 0000000..4753740
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr71077.c
@@ -0,0 +1,18 @@
+/* PR c++/71077  */
+/* { dg-do link { target { i?86-*-* x86_64-*-* } } }  */
+/* { dg-options "-O3 -flto -march=core-avx2" }  */
+
+int *a;
+int b, c, d, e;
+int sched_analyze(void) {
+ for (; b; b++) {
+   c = 0;
+   for (; c < 32; c++)
+     if (b & 1 << c)
+       a[b + c] = d;
+ }
+ return 0;
+}
+
+void schedule_insns(void) { e = sched_analyze(); }
+int main(void) { schedule_insns(); }
diff --git a/gcc/tree-ssa-threadedge.c b/gcc/tree-ssa-threadedge.c
index eca3812..826d620 100644
--- a/gcc/tree-ssa-threadedge.c
+++ b/gcc/tree-ssa-threadedge.c
@@ -573,8 +573,6 @@ simplify_control_stmt_condition_1 (edge e,
 	  enum tree_code rhs_code = gimple_assign_rhs_code (def_stmt);
 	  const tree rhs1 = gimple_assign_rhs1 (def_stmt);
 	  const tree rhs2 = gimple_assign_rhs2 (def_stmt);
-	  const tree zero_cst = build_zero_cst (TREE_TYPE (op0));
-	  const tree one_cst = build_one_cst (TREE_TYPE (op0));
 
 	  /* Is A != 0 ?  */
 	  const tree res1
@@ -589,19 +587,19 @@ simplify_control_stmt_condition_1 (edge e,
 	    {
 	      /* If A == 0 then (A & B) != 0 is always false.  */
 	      if (cond_code == NE_EXPR)
-	        return zero_cst;
+	        return boolean_false_node;
 	      /* If A == 0 then (A & B) == 0 is always true.  */
 	      if (cond_code == EQ_EXPR)
-		return one_cst;
+		return boolean_true_node;
 	    }
 	  else if (rhs_code == BIT_IOR_EXPR && integer_nonzerop (res1))
 	    {
 	      /* If A != 0 then (A | B) != 0 is always true.  */
 	      if (cond_code == NE_EXPR)
-		return one_cst;
+		return boolean_true_node;
 	      /* If A != 0 then (A | B) == 0 is always false.  */
 	      if (cond_code == EQ_EXPR)
-		return zero_cst;
+		return boolean_false_node;
 	    }
 
 	  /* Is B != 0 ?  */
@@ -617,19 +615,19 @@ simplify_control_stmt_condition_1 (edge e,
 	    {
 	      /* If B == 0 then (A & B) != 0 is always false.  */
 	      if (cond_code == NE_EXPR)
-	        return zero_cst;
+	        return boolean_false_node;
 	      /* If B == 0 then (A & B) == 0 is always true.  */
 	      if (cond_code == EQ_EXPR)
-		return one_cst;
+		return boolean_true_node;
 	    }
 	  else if (rhs_code == BIT_IOR_EXPR && integer_nonzerop (res2))
 	    {
 	      /* If B != 0 then (A | B) != 0 is always true.  */
 	      if (cond_code == NE_EXPR)
-		return one_cst;
+		return boolean_true_node;
 	      /* If B != 0 then (A | B) == 0 is always false.  */
 	      if (cond_code == EQ_EXPR)
-		return zero_cst;
+		return boolean_false_node;
 	    }
 
 	  if (res1 != NULL_TREE && res2 != NULL_TREE)
@@ -641,10 +639,10 @@ simplify_control_stmt_condition_1 (edge e,
 		{
 		  /* If A != 0 and B != 0 then (bool)(A & B) != 0 is true.  */
 		  if (cond_code == NE_EXPR)
-		    return one_cst;
+		    return boolean_true_node;
 		  /* If A != 0 and B != 0 then (bool)(A & B) == 0 is false.  */
 		  if (cond_code == EQ_EXPR)
-		    return zero_cst;
+		    return boolean_false_node;
 		}
 
 	      if (rhs_code == BIT_IOR_EXPR
@@ -653,10 +651,10 @@ simplify_control_stmt_condition_1 (edge e,
 		{
 		  /* If A == 0 and B == 0 then (A | B) != 0 is false.  */
 		  if (cond_code == NE_EXPR)
-		    return zero_cst;
+		    return boolean_false_node;
 		  /* If A == 0 and B == 0 then (A | B) == 0 is true.  */
 		  if (cond_code == EQ_EXPR)
-		    return one_cst;
+		    return boolean_true_node;
 		}
 	    }
 	}
-- 
2.9.0.rc0.29.gabd6606

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2016-05-31  8:15 [PATCH] Fix PR tree-optimization/71077 Patrick Palka
2016-05-31 10:28 ` Richard Biener

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