* expmed.c (extract_bit_field_1): Also use a temporary and

	convert_extracted_bit_field when the conversion from ext_mode to
	the target mode requires explicit truncation.

testsuite/
	* gcc.c-torture/execute/20081117-1.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@141960 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0477d27..da96cb5 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2008-11-17  Adam Nemet  <anemet@caviumnetworks.com>
+
+       * expmed.c (extract_bit_field_1): Also use a temporary and
+       convert_extracted_bit_field when the conversion from ext_mode to
+       the target mode requires explicit truncation.
+
 2008-11-17  Richard Sandiford  <rdsandiford@googlemail.com>
 
        * config/mips/mips.h (REG_ALLOC_ORDER): Put accumulators first.

diff --git a/gcc/expmed.c b/gcc/expmed.c
index 0c7e611..70a0d18 100644 (file)
--- a/gcc/expmed.c
+++ b/gcc/expmed.c
@@ -1533,7 +1533,13 @@ extract_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
 
       if (GET_MODE (xtarget) != ext_mode)
        {
-         if (REG_P (xtarget))
+         /* Don't use LHS paradoxical subreg if explicit truncation is needed
+            between the mode of the extraction (word_mode) and the target
+            mode.  Instead, create a temporary and use convert_move to set
+            the target.  */
+         if (REG_P (xtarget)
+             && TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (GET_MODE (xtarget)),
+                                       GET_MODE_BITSIZE (ext_mode)))
            {
              xtarget = gen_lowpart (ext_mode, xtarget);
              if (GET_MODE_SIZE (ext_mode)

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2bc3201..0af6cad 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2008-11-17  Adam Nemet  <anemet@caviumnetworks.com>
+
+       * gcc.c-torture/execute/20081117-1.c: New test.
+
 2008-11-17  Richard Sandiford  <rdsandiford@googlemail.com>
 
        * gcc.target/mips/dspr2-MULT.c: Just check for $ac1 and $ac2.

diff --git a/gcc/testsuite/gcc.c-torture/execute/20081117-1.c b/gcc/testsuite/gcc.c-torture/execute/20081117-1.c
new file mode 100644 (file)
index 0000000..bff7464
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/20081117-1.c
@@ -0,0 +1,24 @@
+extern void abort (void);
+
+struct s
+{
+  unsigned long long a:16;
+  unsigned long long b:32;
+  unsigned long long c:16;
+};
+
+__attribute__ ((noinline)) unsigned
+f (struct s s, unsigned i)
+{
+  return s.b == i;
+}
+
+struct s s = { 1, 0x87654321u, 2};
+
+int
+main ()
+{
+  if (!f (s, 0x87654321u))
+    abort ();
+  return 0;
+}