rtlanal: Fix up replace_rtx [PR105333]

The following testcase FAILs, because replace_rtx replaces a REG with
CONST_WIDE_INT inside of a SUBREG, which is an invalid transformation
because a SUBREG relies on SUBREG_REG having non-VOIDmode but
CONST_WIDE_INT has VOIDmode.

replace_rtx already has code to deal with it, but it was doing
it only for CONST_INTs.  The following patch does it also for
VOIDmode CONST_DOUBLE or CONST_WIDE_INT.

2022-04-22  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/105333
	* rtlanal.c (replace_rtx): Use simplify_subreg or
	simplify_unary_operation if CONST_SCALAR_INT_P rather than just
	CONST_INT_P.

	* gcc.dg/pr105333.c: New test.

(cherry picked from commit 7092b7aea122a91824d048aeb23834cf1d19b1a1)

diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c
index e65d06d5bca699b2f4a803b733cfa9c988523fd3..21a9737422f34ead2a7b16be1603d208557de91a 100644 (file)
--- a/gcc/rtlanal.c
+++ b/gcc/rtlanal.c
@@ -3066,7 +3066,7 @@ replace_rtx (rtx x, rtx from, rtx to, bool all_regs)
     {
       rtx new_rtx = replace_rtx (SUBREG_REG (x), from, to, all_regs);
 
-      if (CONST_INT_P (new_rtx))
+      if (CONST_SCALAR_INT_P (new_rtx))
        {
          x = simplify_subreg (GET_MODE (x), new_rtx,
                               GET_MODE (SUBREG_REG (x)),
@@ -3082,7 +3082,7 @@ replace_rtx (rtx x, rtx from, rtx to, bool all_regs)
     {
       rtx new_rtx = replace_rtx (XEXP (x, 0), from, to, all_regs);
 
-      if (CONST_INT_P (new_rtx))
+      if (CONST_SCALAR_INT_P (new_rtx))
        {
          x = simplify_unary_operation (ZERO_EXTEND, GET_MODE (x),
                                        new_rtx, GET_MODE (XEXP (x, 0)));

diff --git a/gcc/testsuite/gcc.dg/pr105333.c b/gcc/testsuite/gcc.dg/pr105333.c
new file mode 100644 (file)
index 0000000..bd8bd4c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr105333.c
@@ -0,0 +1,21 @@
+/* PR rtl-optimization/105333 */
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-Og -fno-tree-coalesce-vars -fno-tree-fre" } */
+
+int g;
+short s;
+
+static inline unsigned short
+bar (short a, __int128 b)
+{
+  b ^= (unsigned long) -a;
+  __builtin_strncpy ((void *) &s, (void *) &a, 1);
+  b *= 14;
+  return b;
+}
+
+void
+foo (void)
+{
+  g *= (__int128) bar (1, 1);
+}