re PR rtl-optimization/69941 (bogus zero_extend transformation in postreload on aarch64)

	PR rtl-optimization/69941
	* postreload.c (reload_combine_recognize_pattern): Ensure all uses of
	the reg share its mode.

	PR rtl-optimization/69941
	* gcc.dg/torture/pr69941.c: New test.

From-SVN: r234001

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 09a2714..d5fd0d3 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2016-03-04  Bernd Schmidt  <bschmidt@redhat.com>
+
+       PR rtl-optimization/69941
+       * postreload.c (reload_combine_recognize_pattern): Ensure all uses of
+       the reg share its mode.
+
 2016-03-04  Jeff Law  <law@redhat.com>
 
        PR tree-optimization/69196

diff --git a/gcc/postreload.c b/gcc/postreload.c
index 66f691b..61c1ce8 100644 (file)
--- a/gcc/postreload.c
+++ b/gcc/postreload.c
@@ -1057,7 +1057,6 @@ static bool
 reload_combine_recognize_pattern (rtx_insn *insn)
 {
   rtx set, reg, src;
-  unsigned int regno;
 
   set = single_set (insn);
   if (set == NULL_RTX)
@@ -1068,7 +1067,20 @@ reload_combine_recognize_pattern (rtx_insn *insn)
   if (!REG_P (reg) || REG_NREGS (reg) != 1)
     return false;
 
-  regno = REGNO (reg);
+  unsigned int regno = REGNO (reg);
+  machine_mode mode = GET_MODE (reg);
+
+  if (reg_state[regno].use_index < 0
+      || reg_state[regno].use_index >= RELOAD_COMBINE_MAX_USES)
+    return false;
+
+  for (int i = reg_state[regno].use_index;
+       i < RELOAD_COMBINE_MAX_USES; i++)
+    {
+      struct reg_use *use = reg_state[regno].reg_use + i;
+      if (GET_MODE (*use->usep) != mode)
+       return false;
+    }
 
   /* Look for (set (REGX) (CONST_INT))
      (set (REGX) (PLUS (REGX) (REGY)))
@@ -1090,8 +1102,6 @@ reload_combine_recognize_pattern (rtx_insn *insn)
       && REG_P (XEXP (src, 1))
       && rtx_equal_p (XEXP (src, 0), reg)
       && !rtx_equal_p (XEXP (src, 1), reg)
-      && reg_state[regno].use_index >= 0
-      && reg_state[regno].use_index < RELOAD_COMBINE_MAX_USES
       && last_label_ruid < reg_state[regno].use_ruid)
     {
       rtx base = XEXP (src, 1);

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 3fb4fe1..d412efd 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2016-03-04  Bernd Schmidt  <bschmidt@redhat.com>
 
+       PR rtl-optimization/69941
+       * gcc.dg/torture/pr69941.c: New test.
+
        PR c/69824
        * gcc.dg/pr69824.c: New test.
 

diff --git a/gcc/testsuite/gcc.dg/torture/pr69941.c b/gcc/testsuite/gcc.dg/torture/pr69941.c
new file mode 100644 (file)
index 0000000..f15d41a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr69941.c
@@ -0,0 +1,30 @@
+/* { dg-do run } */
+ 
+int a = 0;
+int b = 0;
+int c = 0;
+int e = 0;
+int f = 0;
+int *g = &e;
+ 
+int fn1() { return b ? a : b; }
+ 
+int main() {
+  int h = fn1() <= 0x8000000000000000ULL; // h = 1;
+ 
+  int k = f; // k = 0;
+ 
+  long i = h ? k : k / h; // i = 0;
+ 
+  long l = (unsigned short)(i - 0x1800); // l = 0xe800
+ 
+  i = l ? l : c; // i = 0xe800;
+ 
+  *g = i; // *g = 0xe800; e = 0xe800;
+ 
+  unsigned char result = e >> 9; // result = 0x74;
+
+  if ((int)result != 0x74)
+    __builtin_abort ();
+  return 0;
+}