Fix PowerPC ICE due to secondary_reload ignoring reload replacements

The reason for this PR is that insns emitted by secondary reload
patterns are being generated without taking into account other reloads
that may have occurred.  We run into this problem when an insn has a
pseudo that doesn't get a hard reg, and the pseudo is used in a way
that requires a secondary reload.  In this case the secondary reload
is needed due to gcc generating a 64-bit gpr load from memory insn
with an address offset not a multiple of 4.

	PR target/67378
	* config/rs6000/rs6000.c (rs6000_secondary_reload_gpr): Find
	reload replacement for PRE_MODIFY address reg.

From-SVN: r227573

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d697eddadc0f13f8a8a4c9f985a95eecd15cee89..542abcfe0eccf7287bff50c9968edea281b268b3 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2015-09-09  Alan Modra  <amodra@gmail.com>
+
+       PR target/67378
+       * config/rs6000/rs6000.c (rs6000_secondary_reload_gpr): Find
+       reload replacement for PRE_MODIFY address reg.
+
 2015-09-09  Sebastian Pop  <s.pop@samsung.com>
 
        PR tree-optimization/53852

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 8107bec8e6e379d2c6a9f49a43739b452a73ea24..941592af7447fc1b348014c359b8c411f0833f14 100644 (file)
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -18198,8 +18198,21 @@ rs6000_secondary_reload_gpr (rtx reg, rtx mem, rtx scratch, bool store_p)
 
   if (GET_CODE (addr) == PRE_MODIFY)
     {
+      gcc_assert (REG_P (XEXP (addr, 0))
+                 && GET_CODE (XEXP (addr, 1)) == PLUS
+                 && XEXP (XEXP (addr, 1), 0) == XEXP (addr, 0));
       scratch_or_premodify = XEXP (addr, 0);
-      gcc_assert (REG_P (scratch_or_premodify));
+      if (!HARD_REGISTER_P (scratch_or_premodify))
+       /* If we have a pseudo here then reload will have arranged
+          to have it replaced, but only in the original insn.
+          Use the replacement here too.  */
+       scratch_or_premodify = find_replacement (&XEXP (addr, 0));
+
+      /* RTL emitted by rs6000_secondary_reload_gpr uses RTL
+        expressions from the original insn, without unsharing them.
+        Any RTL that points into the original insn will of course
+        have register replacements applied.  That is why we don't
+        need to look for replacements under the PLUS.  */
       addr = XEXP (addr, 1);
     }
   gcc_assert (GET_CODE (addr) == PLUS || GET_CODE (addr) == LO_SUM);