re PR rtl-optimization/42164 (internal compiler error: in simplify_subreg, at simplif...

2009-12-04  David Daney  <ddaney@caviumnetworks.com>

	PR rtl-optimization/42164
	* combine.c (combine_simplify_rtx): Handle truncation of integer
	constants.

2009-12-04  David Daney  <ddaney@caviumnetworks.com>

	PR rtl-optimization/42164
	* gcc.c-torture/compile/pr42164.c: New test.

From-SVN: r154987

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 450d54d62740510fe1a2edd5c2022c90bb4dc0a2..f01968c789c044e4737113fad0a183d7db838255 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2009-12-04  David Daney  <ddaney@caviumnetworks.com>
+
+       PR rtl-optimization/42164
+       * combine.c (combine_simplify_rtx): Handle truncation of integer
+       constants.
+
 2009-12-04  Richard Guenther  <rguenther@suse.de>
 
        * lto-streamer-out.c (pack_ts_decl_common_value_fields):

diff --git a/gcc/combine.c b/gcc/combine.c
index cdc677d17c73eb0d823af65df38d67d8e7471453..7f3f6da2cea188e71acfa87e3ec4004cc0c434e3 100644 (file)
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -5156,6 +5156,10 @@ combine_simplify_rtx (rtx x, enum machine_mode op0_mode, int in_dest)
               force_to_mode (XEXP (x, 0), GET_MODE (XEXP (x, 0)),
                              GET_MODE_MASK (mode), 0));
 
+      /* We can truncate a constant value and return it.  */
+      if (CONST_INT_P (XEXP (x, 0)))
+       return gen_int_mode (INTVAL (XEXP (x, 0)), mode);
+
       /* Similarly to what we do in simplify-rtx.c, a truncate of a register
         whose value is a comparison can be replaced with a subreg if
         STORE_FLAG_VALUE permits.  */

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 577d18b21633cf1ba2cf606837d9c81b5e6125a3..b20ddd2fdcf595d8973fac3c31fb53217ccd8ebf 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2009-12-04  David Daney  <ddaney@caviumnetworks.com>
+
+       PR rtl-optimization/42164
+       * gcc.c-torture/compile/pr42164.c: New test.
+
 2009-12-04  Eric Botcazou  <ebotcazou@adacore.com>
 
        * gnat.dg/specs/size_attribute1.ads: New test.

diff --git a/gcc/testsuite/gcc.c-torture/compile/pr42164.c b/gcc/testsuite/gcc.c-torture/compile/pr42164.c
new file mode 100644 (file)
index 0000000..7b94aef
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr42164.c
@@ -0,0 +1,25 @@
+typedef struct
+{
+  unsigned long long pte;
+} pte_t;
+pte_t mk_swap_pte (unsigned long offset)
+{
+  pte_t pte;
+  pte.pte = (offset << 40);
+  return pte;
+}
+int pte_file (pte_t pte)
+{
+  return pte.pte & (1 << 4);
+}
+typedef struct
+{
+  unsigned long val;
+} swp_entry_t;
+pte_t swp_entry_to_pte (swp_entry_t entry)
+{
+  swp_entry_t arch_entry;
+  arch_entry = (swp_entry_t){mk_swap_pte (swp_offset (entry)).pte};
+  __BUG_ON ((unsigned long) pte_file ((pte_t) {arch_entry.val}));
+  return (pte_t) {arch_entry.val};
+}