From d16e9a99f948b7080132e0c4830faa4f0eba712c Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Thu, 20 Jun 2013 11:33:43 +0000
Subject: [PATCH] data-streamer-in.c (streamer_read_uhwi): Optimize single byte
case...
2013-06-20 Richard Biener <rguenther@suse.de>
* data-streamer-in.c (streamer_read_uhwi): Optimize single
byte case, inline streamer_read_uchar and defer section
overrun check.
From-SVN: r200239
---
gcc/ChangeLog | 6 ++++++
gcc/data-streamer-in.c | 31 +++++++++++++++++++++++--------
2 files changed, 29 insertions(+), 8 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 249ee2835045..caf85d197560 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2013-06-20 Richard Biener <rguenther@suse.de>
+
+ * data-streamer-in.c (streamer_read_uhwi): Optimize single
+ byte case, inline streamer_read_uchar and defer section
+ overrun check.
+
2013-06-20 Richard Biener <rguenther@suse.de>
PR tree-optimization/57584
diff --git a/gcc/data-streamer-in.c b/gcc/data-streamer-in.c
index e9ceb29312a3..93fe2ff4c3b6 100644
--- a/gcc/data-streamer-in.c
+++ b/gcc/data-streamer-in.c
@@ -120,18 +120,33 @@ bp_unpack_string (struct data_in *data_in, struct bitpack_d *bp)
unsigned HOST_WIDE_INT
streamer_read_uhwi (struct lto_input_block *ib)
{
- unsigned HOST_WIDE_INT result = 0;
- int shift = 0;
+ unsigned HOST_WIDE_INT result;
+ int shift;
unsigned HOST_WIDE_INT byte;
+ unsigned int p = ib->p;
+ unsigned int len = ib->len;
- while (true)
+ const char *data = ib->data;
+ result = data[p++];
+ if ((result & 0x80) != 0)
{
- byte = streamer_read_uchar (ib);
- result |= (byte & 0x7f) << shift;
- shift += 7;
- if ((byte & 0x80) == 0)
- return result;
+ result &= 0x7f;
+ shift = 7;
+ do
+ {
+ byte = data[p++];
+ result |= (byte & 0x7f) << shift;
+ shift += 7;
+ }
+ while ((byte & 0x80) != 0);
}
+
+ /* We check for section overrun after the fact for performance reason. */
+ if (p > len)
+ lto_section_overrun (ib);
+
+ ib->p = p;
+ return result;
}
--
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