rs6000: cannot_force_const_mem for HIGH code rtx[PR106460]

As the issue in PR106460, a rtx 'high:DI (symbol_ref:DI ("var_48")' is tried
to store into constant pool and ICE occur.  But actually, this rtx represents
partial incomplete address and can not be put into a .rodata section.

This patch updates rs6000_cannot_force_const_mem to return true for rtx(s) with
HIGH code, because these rtx(s) indicate part of address and are not ok for
constant pool.

Below are some examples:
(high:DI (const:DI (plus:DI (symbol_ref:DI ("xx") (const_int 12 [0xc])))))
(high:DI (symbol_ref:DI ("var_1")..)))

	PR target/106460

gcc/ChangeLog:

	* config/rs6000/rs6000.cc (rs6000_cannot_force_const_mem): Return true
	for HIGH code rtx.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr106460.c: New test.

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 01e5bbc..a85d763 100644 (file)
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -9759,8 +9759,11 @@ rs6000_init_stack_protect_guard (void)
 static bool
 rs6000_cannot_force_const_mem (machine_mode mode ATTRIBUTE_UNUSED, rtx x)
 {
-  if (GET_CODE (x) == HIGH
-      && GET_CODE (XEXP (x, 0)) == UNSPEC)
+  /* If GET_CODE (x) is HIGH, the 'X' represets the high part of a symbol_ref.
+     It can not be put into a constant pool.  e.g.
+     (high:DI (unspec:DI [(symbol_ref/u:DI ("*.LC0")..)
+     (high:DI (symbol_ref:DI ("var")..)).  */
+  if (GET_CODE (x) == HIGH)
     return true;
 
   /* A TLS symbol in the TOC cannot contain a sum.  */

diff --git a/gcc/testsuite/gcc.target/powerpc/pr106460.c b/gcc/testsuite/gcc.target/powerpc/pr106460.c
new file mode 100644 (file)
index 0000000..aae4b01
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr106460.c
@@ -0,0 +1,12 @@
+/* { dg-require-effective-target power10_ok } */
+/* { dg-options "-O1 -mdejagnu-cpu=power10" } */
+
+/* (high:DI (symbol_ref:DI ("var_48")..))) should not cause ICE. */
+extern short var_48;
+void
+foo (double *r)
+{
+  if (var_48)
+    *r = 1234.5678;
+}
+