re PR middle-end/55882 (unaligned load/store : incorrect struct offset)

2013-01-15  Richard Biener  <rguenther@suse.de>

	PR middle-end/55882
	* emit-rtl.c (set_mem_attributes_minus_bitpos): Correctly
	account for bitpos when computing alignment.

	* gcc.dg/torture/pr55882.c: New testcase.

From-SVN: r195194

4 files changed, 111 insertions, 1 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index efe553b..cb85e0b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2013-01-15  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/55882
+	* emit-rtl.c (set_mem_attributes_minus_bitpos): Correctly
+	account for bitpos when computing alignment.
+
 2013-01-15  Vladimir Yakovlev  <vladimir.b.yakovlev@intel.com>
 
 	* config/i386/i386-c.c (ix86_target_macros_internal): New case.
diff --git a/gcc/emit-rtl.c b/gcc/emit-rtl.c
index e7e904a..2987bc9 100644
--- a/gcc/emit-rtl.c
+++ b/gcc/emit-rtl.c
@@ -1839,7 +1839,12 @@ set_mem_attributes_minus_bitpos (rtx ref, tree t, int objectp,
 
       if (!align_computed)
 	{
-	  unsigned int obj_align = get_object_alignment (t);
+	  unsigned int obj_align;
+	  unsigned HOST_WIDE_INT obj_bitpos;
+	  get_object_alignment_1 (t, &obj_align, &obj_bitpos);
+	  obj_bitpos = (obj_bitpos - bitpos) & (obj_align - 1);
+	  if (obj_bitpos != 0)
+	    obj_align = (obj_bitpos & -obj_bitpos);
 	  attrs.align = MAX (attrs.align, obj_align);
 	}
     }
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a80f16b..c286a87 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2013-01-15  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/55882
+	* gcc.dg/torture/pr55882.c: New testcase.
+
 2013-01-15  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/55955
diff --git a/gcc/testsuite/gcc.dg/torture/pr55882.c b/gcc/testsuite/gcc.dg/torture/pr55882.c
new file mode 100644
index 0000000..fd2276e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr55882.c
@@ -0,0 +1,94 @@
+/* { dg-do run } */
+
+typedef enum
+{
+  PVT_A = 0,
+  PVT_B = 1,
+  PVT_CONFIG = 2,
+  PVT_RESERVED3 = 3,
+} T_CR_SELECT;
+
+typedef enum
+{
+  STD_ULOGIC_0 = 0,
+  STD_ULOGIC_1 = 1,
+} STD_ULOGIC;
+
+typedef struct
+{
+  unsigned char rtp : 3;
+  unsigned char rtn : 3;
+} C;
+
+typedef struct
+{
+  unsigned char nd;
+  unsigned char pd;
+  unsigned char rtn;
+  unsigned char rtp;
+} A;
+
+typedef struct
+{
+  unsigned short reserved : 14;
+  unsigned char Z_rx_enable : 2;
+  A pvt;
+} B;
+
+typedef struct
+{
+  B cr_dsclk_q3;
+  B cr_data_q3;
+  B cr_addr_q3;
+  B cr_cmd_q3;
+  B cr_pres_q3;
+  C cr_vref_q3[6];
+  unsigned char pres_disable;
+  unsigned char pres_drive_high;
+  unsigned char c_enab_120;
+  STD_ULOGIC clk_tximp;
+  STD_ULOGIC dqs_tximp;
+  STD_ULOGIC cmd_tximp;
+  STD_ULOGIC data_tximp;
+  STD_ULOGIC dqs_rxterm;
+  STD_ULOGIC data_rxterm;
+  T_CR_SELECT cr_clk_sel;
+  unsigned char cr_clk : 5;
+  T_CR_SELECT cr_dsclk_odd_sel;
+  unsigned char cr_dsclk_odd : 5;
+  T_CR_SELECT cr_dsclk_even_sel;
+  unsigned char cr_dsclk_even : 5;
+  T_CR_SELECT cr_data_sel;
+  unsigned char cr_data : 5;
+  T_CR_SELECT cr_vref_sel;
+  unsigned char cr_vref : 5;
+  T_CR_SELECT cr_others_sel;
+  unsigned char cr_others : 5;
+} CONFIG;
+
+typedef struct
+{
+  unsigned char enable_monitor;
+  unsigned short step_out_pointer : 12;
+  unsigned short hold_out_pointer : 12;
+  unsigned short enable_wr_dqs : 12;
+  unsigned short use_alt_rd_dqs : 12;
+  CONFIG io_buf;
+} mystruct;
+
+unsigned short __attribute__((noinline,noclone))
+testfunction(unsigned i)
+{
+  mystruct dmfe[8];
+  dmfe[0].use_alt_rd_dqs = 1;
+  dmfe[i].use_alt_rd_dqs = 0;
+  return dmfe[0].use_alt_rd_dqs;
+}
+
+extern void abort (void);
+int main ()
+{
+  if (testfunction(0) != 0) 
+    abort ();
+  return 0;
+}