PR target/34403

	* config/i386/i386.c (ix86_expand_movmem): Punt if the count is large.
	(ix86_expand_setmem): Likewise.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@130753 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 9 insertions, 1 deletions

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 9d2c14438a9..ebbf48957ba 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -15282,7 +15282,7 @@ smallest_pow2_greater_than (int val)
 }
 
 /* Expand string move (memcpy) operation.  Use i386 string operations when
-   profitable.  expand_clrmem contains similar code. The code depends upon
+   profitable.  expand_setmem contains similar code.  The code depends upon
    architecture, block size and alignment, but always has the same
    overall structure:
 
@@ -15333,6 +15333,10 @@ ix86_expand_movmem (rtx dst, rtx src, rtx count_exp, rtx align_exp,
   if (CONST_INT_P (expected_size_exp) && count == 0)
     expected_size = INTVAL (expected_size_exp);
 
+  /* Make sure we don't need to care about overflow later on.  */
+  if (count > ((unsigned HOST_WIDE_INT) 1 << 30))
+    return 0;
+
   /* Step 0: Decide on preferred algorithm, desired alignment and
      size of chunks to be copied by main loop.  */
 
@@ -15657,6 +15661,10 @@ ix86_expand_setmem (rtx dst, rtx count_exp, rtx val_exp, rtx align_exp,
   if (CONST_INT_P (expected_size_exp) && count == 0)
     expected_size = INTVAL (expected_size_exp);
 
+  /* Make sure we don't need to care about overflow later on.  */
+  if (count > ((unsigned HOST_WIDE_INT) 1 << 30))
+    return 0;
+
   /* Step 0: Decide on preferred algorithm, desired alignment and
      size of chunks to be copied by main loop.  */