tree-call-cdce: If !HONOR_NANS do not make code with NaNs (PR88055)

If we don't HONOR_NANS we should not try to use any unordered
comparison results.  Best case those will just be optimized away;
realistically, they ICE.  For example, the rs6000 backend has some
code that specifically checks we never do this.

	PR tree-optimization/88055
	* tree-call-cdce.c (comparison_code_if_no_nans): New function.
	(gen_one_condition): Use it if !HONOR_NANS.

From-SVN: r270460

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5327dcda6f39a051524751637f7b2f90a8ae8132..493aaeb84b65187e11ff3bbde092648352c833f6 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2019-04-19  Segher Boessenkool  <segher@kernel.crashing.org>
+
+       PR tree-optimization/88055
+       * tree-call-cdce.c (comparison_code_if_no_nans): New function.
+       (gen_one_condition): Use it if !HONOR_NANS.
+
 2019-04-19  Jakub Jelinek  <jakub@redhat.com>
 
        PR middle-end/90139

diff --git a/gcc/tree-call-cdce.c b/gcc/tree-call-cdce.c
index 2b1e9340bcebb25e73e9cb80b88fb324dbd3c2e1..2e482b37ea25b7571632c297d7a42b2555bd1fd3 100644 (file)
--- a/gcc/tree-call-cdce.c
+++ b/gcc/tree-call-cdce.c
@@ -362,6 +362,40 @@ can_guard_call_p (gimple *call)
          || find_fallthru_edge (gimple_bb (call)->succs));
 }
 \f
+/* For a comparison code return the comparison code we should use if we don't
+   HONOR_NANS.  */
+
+static enum tree_code
+comparison_code_if_no_nans (tree_code code)
+{
+  switch (code)
+    {
+    case UNLT_EXPR:
+      return LT_EXPR;
+    case UNGT_EXPR:
+      return GT_EXPR;
+    case UNLE_EXPR:
+      return LE_EXPR;
+    case UNGE_EXPR:
+      return GE_EXPR;
+    case UNEQ_EXPR:
+      return EQ_EXPR;
+    case LTGT_EXPR:
+      return NE_EXPR;
+
+    case LT_EXPR:
+    case GT_EXPR:
+    case LE_EXPR:
+    case GE_EXPR:
+    case EQ_EXPR:
+    case NE_EXPR:
+      return code;
+
+    default:
+      gcc_unreachable ();
+    }
+}
+
 /* A helper function to generate gimple statements for one bound
    comparison, so that the built-in function is called whenever
    TCODE <ARG, LBUB> is *false*.  TEMP_NAME1/TEMP_NAME2 are names
@@ -378,6 +412,9 @@ gen_one_condition (tree arg, int lbub,
                   vec<gimple *> conds,
                    unsigned *nconds)
 {
+  if (!HONOR_NANS (arg))
+    tcode = comparison_code_if_no_nans (tcode);
+
   tree lbub_real_cst, lbub_cst, float_type;
   tree temp, tempn, tempc, tempcn;
   gassign *stmt1;