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.
This patch fixes it. Bootstrapped and tested on powerpc64-linux
{-m32,-m64}. Is this okay for trunk?
Segher
2019-04-18 Segher Boessenkool <seg...@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.
---
gcc/tree-call-cdce.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/gcc/tree-call-cdce.c b/gcc/tree-call-cdce.c
index 2b1e934..2e482b3 100644
--- 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));
}
+/* 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;
--
1.8.3.1
