Hi!
We ICE on the following testcase at -O3 on x86_64-linux, because
gimple folding attempts to simplify FLOAT_EXPR conversion of
signed V4SI to V4SF feeding FIX_TRUNC_EXPR to unsigned V4SI
into a FIX_TRUNC_EXPR with unsigned V4SI lhs and signed V4SI rhs1,
which is invalid GIMPLE.
All the other simplifications in the same iterator block don't
optimize anything for vector types, and I can't find out any case
where something like this would be beneficial for vector types.
These days we represent source level casts of vectors to same sized
integers as VIEW_CONVERT_EXPR, which isn't handled in here,
and *_prec doesn't really mean what it tests for vector types
(it is log2 of number of elements), vector integer or float widening
is not represented using convert/float/fix_trunc, but using VEC_PERM_EXPR,
VEC_UNPACK*_{LO,HI}_EXPR etc.
I've bootstrapped/regtested with a logging variant and if
(inside_vec || inter_vec || final_vec) is true, we (mis)optimize
anything only on the testcase included in the patch and on
gfortran.dg/stfunc_4.f90 testcase, in both cases it is
V4SI -> V4SF -> V4SI, which we really shouldn't be optimizing,
because SF mode obviously can't represent all integers exactly.
So, this patch disables optimizing vectors.
Ok for trunk/5.2 if bootstrap/regtest succeeds?
For 4.9/4.8 a similar patch will be needed, but to
fold-const.c/tree-ssa-forwprop.c instead of match.pd.
2015-05-21 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/66233
* match.pd (ocvt (icvt@1 @0)): Don't handle vector types.
Simplify.
* gcc.c-torture/execute/pr66233.c: New test.
--- gcc/match.pd.jj 2015-05-19 15:53:43.000000000 +0200
+++ gcc/match.pd 2015-05-21 16:21:35.627916502 +0200
@@ -730,16 +730,12 @@ (define_operator_list inverted_tcc_compa
(for integers). Avoid this if the final type is a pointer since
then we sometimes need the middle conversion. Likewise if the
final type has a precision not equal to the size of its mode. */
- (if (((inter_int && inside_int)
- || (inter_float && inside_float)
- || (inter_vec && inside_vec))
+ (if (((inter_int && inside_int) || (inter_float && inside_float))
+ && (final_int || final_float)
&& inter_prec >= inside_prec
- && (inter_float || inter_vec
- || inter_unsignedp == inside_unsignedp)
- && ! (final_prec != GET_MODE_PRECISION (element_mode (type))
- && element_mode (type) == element_mode (inter_type))
- && ! final_ptr
- && (! final_vec || inter_prec == inside_prec))
+ && (inter_float || inter_unsignedp == inside_unsignedp)
+ && ! (final_prec != GET_MODE_PRECISION (TYPE_MODE (type))
+ && TYPE_MODE (type) == TYPE_MODE (inter_type)))
(ocvt @0))
/* If we have a sign-extension of a zero-extended value, we can
--- gcc/testsuite/gcc.c-torture/execute/pr66233.c.jj 2015-05-21
17:13:32.639713225 +0200
+++ gcc/testsuite/gcc.c-torture/execute/pr66233.c 2015-05-21
17:10:57.000000000 +0200
@@ -0,0 +1,22 @@
+/* PR tree-optimization/66233 */
+
+unsigned int v[8];
+
+__attribute__((noinline, noclone)) void
+foo (void)
+{
+ int i;
+ for (i = 0; i < 8; i++)
+ v[i] = (float) i;
+}
+
+int
+main ()
+{
+ unsigned int i;
+ foo ();
+ for (i = 0; i < 8; i++)
+ if (v[i] != i)
+ __builtin_abort ();
+ return 0;
+}
Jakub
