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Re: patch to fix constant math - first small patch - patch ping for the next stage 1

From: Kenneth Zadeck <zadeck at naturalbridge dot com>
To: Richard Biener <richard dot guenther at gmail dot com>
Cc: "Joseph S. Myers" <joseph at codesourcery dot com>, Mike Stump <mikestump at comcast dot net>, gcc-patches <gcc-patches at gcc dot gnu dot org>, rdsandiford at googlemail dot com, Ian Lance Taylor <iant at google dot com>
Date: Tue, 02 Apr 2013 09:49:03 -0400
Subject: Re: patch to fix constant math - first small patch - patch ping for the next stage 1
References: <506C72C7 dot 7090207 at naturalbridge dot com> <506DD085 dot 7080608 at naturalbridge dot com> <87txuaox52 dot fsf at talisman dot home> <CAFiYyc1GP46Sf9Tr=YWL1EhWwhcfRFBQoiH8jV-PZv-krsWJmg at mail dot gmail dot com> <87lifli6oj dot fsf at sandifor-thinkpad dot stglab dot manchester dot uk dot ibm dot com> <CAFiYyc1RYvJ-2_6WaYosA3qm5JhiGhmXnczX3DCNfKt_zg46+g at mail dot gmail dot com> <87ehldi2kr dot fsf at sandifor-thinkpad dot stglab dot manchester dot uk dot ibm dot com> <CAFiYyc0B27i23X8Sg+=yOd_SqKedB3RunBDs4b-Jm-fSAD-hwA at mail dot gmail dot com> <87a9w1hzq1 dot fsf at sandifor-thinkpad dot stglab dot manchester dot uk dot ibm dot com> <CAFiYyc0Sj3+yBXRjLUG=0=_NGQiU1VqJk35hjsWqHR9bCnqspg at mail dot gmail dot com> <506F0C1A dot 5010705 at naturalbridge dot com> <87lifkhlo9 dot fsf at sandifor-thinkpad dot stglab dot manchester dot uk dot ibm dot com> <506F5B50 dot 2040800 at naturalbridge dot com> <Pine dot LNX dot 4 dot 64 dot 1210060013110 dot 3565 at digraph dot polyomino dot org dot uk> <512D51DE dot 6010005 at naturalbridge dot com> <CAFiYyc0FQTmnPqC44ks+EH=Rjri97gdW=CKDZM0A7pX7C8_XSA at mail dot gmail dot com> <51587791 dot 9090105 at naturalbridge dot com> <CAFiYyc0QSSWxu_6Lk__APTwD8GRE9Zv1tZU6evtGnQbF1dxDNQ at mail dot gmail dot com>

Richard,

did everything that you asked here. bootstrapped and regtested onx86-64. ok to commit?


kenny

On 04/02/2013 05:38 AM, Richard Biener wrote:

On Sun, Mar 31, 2013 at 7:51 PM, Kenneth Zadeck
<zadeck@naturalbridge.com> wrote:

richard,

I was able to add everything except for the checking asserts.    While I
think that this is a reasonable idea, it is difficult to add that to a
function that is defined in hwint.h because of circular includes.   I could
move this another file (though this appears to be the logical correct place
for it), or we can do without the asserts.

The context is that [sz]ext_hwi is that are used are over the compiler but
are generally written out long.   The wide-int class uses them also, but
wide-int did not see like the right place for them to live and i believe
that you suggested that i move them.

ok to commit, or do you have a suggested resolution to the assert issue?

Yes, do

#ifdef ENABLE_CHECKING
extern HOST_WIDE_INT sext_hwi (HOST_WIDE_INT, unsigned int);
#else
+/* Sign extend SRC starting from PREC.  */
+
+static inline HOST_WIDE_INT
+sext_hwi (HOST_WIDE_INT src, unsigned int prec)
+{
+  if (prec == HOST_BITS_PER_WIDE_INT)
+    return src;
+  else
+    {
         int shift = HOST_BITS_PER_WIDE_INT - prec;
+      return (src << shift) >> shift;
+    }
+}
#endif

and for ENABLE_CHECKING only provide an out-of-line implementation
in hwint.c.  That's how we did it with abs_hwi (well, we just do not provide
an inline variant there - that's another possibility).

Note that hwint.h is always included after config.h so the ENABLE_CHECKING
definition should be available.

Richard.

kenny


On 03/27/2013 10:13 AM, Richard Biener wrote:

On Wed, Feb 27, 2013 at 1:22 AM, Kenneth Zadeck
<zadeck@naturalbridge.com> wrote:

Here is the first of my wide int patches with joseph's comments and the
patch rot removed.

I would like to get these pre approved for the next stage 1.

+      int shift = HOST_BITS_PER_WIDE_INT - (prec &
(HOST_BITS_PER_WIDE_INT - 1));

I think this should gcc_checking_assert that prec is not out of range
(any reason why prec is signed int and not unsigned int?) rather than
ignore bits in prec.

+static inline HOST_WIDE_INT
+zext_hwi (HOST_WIDE_INT src, int prec)
+{
+  if (prec == HOST_BITS_PER_WIDE_INT)
+    return src;
+  else
+    return src & (((HOST_WIDE_INT)1
+                  << (prec & (HOST_BITS_PER_WIDE_INT - 1))) - 1);
+}

likewise.  Also I'm not sure I agree about the signedness of the result /
src.
zext_hwi (-1, HOST_BITS_PER_WIDE_INT) < 0 is true which is odd.

The patch misses context of uses, so I'm not sure what the above functions
are intended to do.

Richard.

On 10/05/2012 08:14 PM, Joseph S. Myers wrote:

On Fri, 5 Oct 2012, Kenneth Zadeck wrote:

+# define HOST_HALF_WIDE_INT_PRINT "h"

This may cause problems on hosts not supporting %hd (MinGW?), and
there's
no real need for using "h" here given the promotion of short to int; you
can just use "" (rather than e.g. needing special handling in
xm-mingw32.h
like is done for HOST_LONG_LONG_FORMAT).

Attachment: p1-5.clog
Description: Text document

diff --git a/gcc/hwint.c b/gcc/hwint.c
index 330b42c..7e5b85c 100644
--- a/gcc/hwint.c
+++ b/gcc/hwint.c
@@ -204,3 +204,33 @@ least_common_multiple (HOST_WIDE_INT a, HOST_WIDE_INT b)
 {
   return mul_hwi (abs_hwi (a) / gcd (a, b), abs_hwi (b));
 }
+
+#ifndef ENABLE_CHECKING
+/* Sign extend SRC starting from PREC.  */
+
+HOST_WIDE_INT
+sext_hwi (HOST_WIDE_INT src, unsigned int prec)
+{
+  if (prec == HOST_BITS_PER_WIDE_INT)
+    return src;
+  else
+    {
+      int shift = HOST_BITS_PER_WIDE_INT - 
+	(prec & (HOST_BITS_PER_WIDE_INT - 1));
+      return (src << shift) >> shift;
+    }
+}
+
+/* Zero extend SRC starting from PREC.  */
+
+unsigned HOST_WIDE_INT
+zext_hwi (unsigned HOST_WIDE_INT src, unsigned int prec)
+{
+  if (prec == HOST_BITS_PER_WIDE_INT)
+    return src;
+  else
+    return src & (((HOST_WIDE_INT)1
+		   << (prec & (HOST_BITS_PER_WIDE_INT - 1))) - 1);
+}
+
+#endif
diff --git a/gcc/hwint.h b/gcc/hwint.h
index da62fad..9dddf05 100644
--- a/gcc/hwint.h
+++ b/gcc/hwint.h
@@ -76,6 +76,40 @@ extern char sizeof_long_long_must_be_8[sizeof(long long) == 8 ? 1 : -1];
 # endif
 #endif
 
+/* Print support for half a host wide int.  */
+#define HOST_BITS_PER_HALF_WIDE_INT (HOST_BITS_PER_WIDE_INT / 2)
+#if HOST_BITS_PER_HALF_WIDE_INT == HOST_BITS_PER_LONG
+# define HOST_HALF_WIDE_INT long
+# define HOST_HALF_WIDE_INT_PRINT HOST_LONG_FORMAT
+# define HOST_HALF_WIDE_INT_PRINT_C "L"
+# define HOST_HALF_WIDE_INT_PRINT_DEC "%" HOST_HALF_WIDE_INT_PRINT "d"
+# define HOST_HALF_WIDE_INT_PRINT_DEC_C HOST_HALF_WIDE_INT_PRINT_DEC HOST_HALF_WIDE_INT_PRINT_C
+# define HOST_HALF_WIDE_INT_PRINT_UNSIGNED "%" HOST_HALF_WIDE_INT_PRINT "u"
+# define HOST_HALF_WIDE_INT_PRINT_HEX "%#" HOST_HALF_WIDE_INT_PRINT "x"
+# define HOST_HALF_WIDE_INT_PRINT_HEX_PURE "%" HOST_HALF_WIDE_INT_PRINT "x"
+#elif HOST_BITS_PER_HALF_WIDE_INT == HOST_BITS_PER_INT
+# define HOST_HALF_WIDE_INT int
+# define HOST_HALF_WIDE_INT_PRINT ""
+# define HOST_HALF_WIDE_INT_PRINT_C ""
+# define HOST_HALF_WIDE_INT_PRINT_DEC "%" HOST_HALF_WIDE_INT_PRINT "d"
+# define HOST_HALF_WIDE_INT_PRINT_DEC_C HOST_HALF_WIDE_INT_PRINT_DEC HOST_HALF_WIDE_INT_PRINT_C
+# define HOST_HALF_WIDE_INT_PRINT_UNSIGNED "%" HOST_HALF_WIDE_INT_PRINT "u"
+# define HOST_HALF_WIDE_INT_PRINT_HEX "%#" HOST_HALF_WIDE_INT_PRINT "x"
+# define HOST_HALF_WIDE_INT_PRINT_HEX_PURE "%" HOST_HALF_WIDE_INT_PRINT "x"
+#elif HOST_BITS_PER_HALF_WIDE_INT == HOST_BITS_PER_SHORT
+# define HOST_HALF_WIDE_INT short
+# define HOST_HALF_WIDE_INT_PRINT ""
+# define HOST_HALF_WIDE_INT_PRINT_C ""
+# define HOST_HALF_WIDE_INT_PRINT_DEC "%" HOST_HALF_WIDE_INT_PRINT "d"
+# define HOST_HALF_WIDE_INT_PRINT_DEC_C HOST_HALF_WIDE_INT_PRINT_DEC HOST_HALF_WIDE_INT_PRINT_C
+# define HOST_HALF_WIDE_INT_PRINT_UNSIGNED "%" HOST_HALF_WIDE_INT_PRINT "u"
+# define HOST_HALF_WIDE_INT_PRINT_HEX "%#" HOST_HALF_WIDE_INT_PRINT "x"
+# define HOST_HALF_WIDE_INT_PRINT_HEX_PURE "%" HOST_HALF_WIDE_INT_PRINT "x"
+#else
+#error Please add support for HOST_HALF_WIDE_INT
+#endif
+
+
 #define HOST_WIDE_INT_1 HOST_WIDE_INT_C(1)
 
 /* This is a magic identifier which allows GCC to figure out the type
@@ -93,9 +127,13 @@ typedef HOST_WIDE_INT __gcc_host_wide_int__;
 # if HOST_BITS_PER_WIDE_INT == 64
 #  define HOST_WIDE_INT_PRINT_DOUBLE_HEX \
      "0x%" HOST_LONG_FORMAT "x%016" HOST_LONG_FORMAT "x"
+#  define HOST_WIDE_INT_PRINT_PADDED_HEX \
+     "%016" HOST_LONG_FORMAT "x"
 # else
 #  define HOST_WIDE_INT_PRINT_DOUBLE_HEX \
      "0x%" HOST_LONG_FORMAT "x%08" HOST_LONG_FORMAT "x"
+#  define HOST_WIDE_INT_PRINT_PADDED_HEX \
+     "%08" HOST_LONG_FORMAT "x"
 # endif
 #else
 # define HOST_WIDE_INT_PRINT HOST_LONG_LONG_FORMAT
@@ -103,6 +141,8 @@ typedef HOST_WIDE_INT __gcc_host_wide_int__;
   /* We can assume that 'long long' is at least 64 bits.  */
 # define HOST_WIDE_INT_PRINT_DOUBLE_HEX \
     "0x%" HOST_LONG_LONG_FORMAT "x%016" HOST_LONG_LONG_FORMAT "x"
+# define HOST_WIDE_INT_PRINT_PADDED_HEX \
+    "%016" HOST_LONG_LONG_FORMAT "x"
 #endif /* HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_LONG */
 
 #define HOST_WIDE_INT_PRINT_DEC "%" HOST_WIDE_INT_PRINT "d"
@@ -276,4 +316,42 @@ extern HOST_WIDE_INT pos_mul_hwi (HOST_WIDE_INT, HOST_WIDE_INT);
 extern HOST_WIDE_INT mul_hwi (HOST_WIDE_INT, HOST_WIDE_INT);
 extern HOST_WIDE_INT least_common_multiple (HOST_WIDE_INT, HOST_WIDE_INT);
 
+/* Sign extend SRC starting from PREC.  */
+
+#ifdef ENABLE_CHECKING
+extern HOST_WIDE_INT sext_hwi (HOST_WIDE_INT, unsigned int);
+#else
+static inline HOST_WIDE_INT
+sext_hwi (HOST_WIDE_INT src, unsigned int prec)
+{
+  gcc_checking_assert (prec <= HOST_BITS_PER_WIDE_INT);
+
+  if (prec == HOST_BITS_PER_WIDE_INT)
+    return src;
+  else
+    {
+      int shift = HOST_BITS_PER_WIDE_INT - 
+	(prec & (HOST_BITS_PER_WIDE_INT - 1));
+      return (src << shift) >> shift;
+    }
+}
+#endif
+
+/* Zero extend SRC starting from PREC.  */
+#ifdef ENABLE_CHECKING
+extern unsigned HOST_WIDE_INT zext_hwi (unsigned HOST_WIDE_INT, unsigned int);
+#else
+static inline unsigned HOST_WIDE_INT
+zext_hwi (unsigned HOST_WIDE_INT src, unsigned int prec)
+{
+  gcc_checking_assert (prec <= HOST_BITS_PER_WIDE_INT);
+
+  if (prec == HOST_BITS_PER_WIDE_INT)
+    return src;
+  else
+    return src & (((HOST_WIDE_INT)1
+		   << (prec & (HOST_BITS_PER_WIDE_INT - 1))) - 1);
+}
+#endif
+
 #endif /* ! GCC_HWINT_H */

Follow-Ups:
- Re: patch to fix constant math - first small patch - patch ping for the next stage 1
  - From: Richard Biener

References:
- Re: patch to fix constant math - first small patch - patch ping for the next stage 1
  - From: Richard Biener

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