@@ -999,10 +999,27 @@ try_fwprop_subst (df_ref use, rtx *loc,
making a new one if one does not already exist. */
if (set_reg_equal)
{
- if (dump_file)
- fprintf (dump_file, " Setting REG_EQUAL note\n");
+ /* If there are any paradoxical SUBREGs, don't add REG_EQUAL note,
+ because the bits in there can be anything and so might not
+ match the REG_EQUAL note content. See PR70574. */
+ subrtx_var_iterator::array_type array;
+ FOR_EACH_SUBRTX_VAR (iter, array, *loc, NONCONST)
+ {
+ rtx x = *iter;
+ if (SUBREG_P (x) && paradoxical_subreg_p (x))
+ {
+ set_reg_equal = false;
+ break;
+ }
+ }
+
+ if (set_reg_equal)
+ {
+ if (dump_file)
+ fprintf (dump_file, " Setting REG_EQUAL note\n");
- note = set_unique_reg_note (insn, REG_EQUAL, copy_rtx (new_rtx));
+ note = set_unique_reg_note (insn, REG_EQUAL, copy_rtx (new_rtx));
+ }
}
}
@@ -1300,14 +1317,19 @@ forward_propagate_and_simplify (df_ref u
that isn't mentioned in USE_SET, as the note would be invalid
otherwise. We also don't want to install a note if we are merely
propagating a pseudo since verifying that this pseudo isn't dead
- is a pain; moreover such a note won't help anything. */
+ is a pain; moreover such a note won't help anything.
+ If the use is a paradoxical subreg, make sure we don't add a
+ REG_EQUAL note for it, because it is not equivalent, it is one
+ possible value for it, but we can't rely on it holding that value.
+ See PR70574. */
set_reg_equal = (note == NULL_RTX
&& REG_P (SET_DEST (use_set))
&& !REG_P (src)
&& !(GET_CODE (src) == SUBREG
&& REG_P (SUBREG_REG (src)))
&& !reg_mentioned_p (SET_DEST (use_set),
- SET_SRC (use_set)));
+ SET_SRC (use_set))
+ && !paradoxical_subreg_p (DF_REF_REG (use)));
}
if (GET_MODE (*loc) == VOIDmode)
@@ -0,0 +1,26 @@
+/* PR rtl-optimization/70574 */
+/* { dg-do run { target lp64 } } */
+/* { dg-require-effective-target avx2 } */
+/* { dg-options "-O -frerun-cse-after-loop -fno-tree-ccp -mcmodel=medium -mavx2" } */
+/* { dg-additional-options "-fPIC" { target fpic } } */
+
+#include "avx2-check.h"
+
+typedef char A __attribute__((vector_size (32)));
+typedef short B __attribute__((vector_size (32)));
+
+int
+foo (int x, __int128 y, __int128 z, A w)
+{
+ y <<= 64;
+ w *= (A) { 0, -1, z, 0, ~y };
+ return w[0] + ((B) { x, 0, y, 0, -1 } | 1)[4];
+}
+
+static void
+avx2_test ()
+{
+ int x = foo (0, 0, 0, (A) {});
+ if (x != -1)
+ __builtin_abort ();
+}