Fix PR44281, bad RA with global regs.

	PR rtl-optimization/44281
	* hard-reg-set.h (struct target_hard_regs): New field
	x_fixed_nonglobal_reg_set.
	(fixed_nonglobal_reg_set): New macro.
	* reginfo.c (init_reg_sets_1): Initialize it.
	* ira.c (setup_alloc_regs): Use fixed_nonglobal_reg_set instead
	of fixed_reg_set.
	* df-scan.c (df_insn_refs_collect): Asms may reference global regs.

testsuite/
	PR rtl-optimization/44281
	* gcc.target/i386/pr44281.c: New test.

From-SVN: r235809

7 files changed, 53 insertions, 3 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ffe45b7..608f64b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2016-05-03  Bernd Schmidt  <bschmidt@redhat.com>
+
+	PR rtl-optimization/44281
+	* hard-reg-set.h (struct target_hard_regs): New field
+	x_fixed_nonglobal_reg_set.
+	(fixed_nonglobal_reg_set): New macro.
+	* reginfo.c (init_reg_sets_1): Initialize it.
+	* ira.c (setup_alloc_regs): Use fixed_nonglobal_reg_set instead
+	of fixed_reg_set.
+	* df-scan.c (df_insn_refs_collect): Asms may reference global regs.
+
 2016-05-03  bin cheng  <bin.cheng@arm.com>
 
 	PR tree-optimization/56541
diff --git a/gcc/df-scan.c b/gcc/df-scan.c
index e6d01d6..19d8e0f 100644
--- a/gcc/df-scan.c
+++ b/gcc/df-scan.c
@@ -3223,11 +3223,22 @@ df_insn_refs_collect (struct df_collection_rec *collection_rec,
         }
     }
 
+  int flags = (is_cond_exec) ? DF_REF_CONDITIONAL : 0;
   /* For CALL_INSNs, first record DF_REF_BASE register defs, as well as
      uses from CALL_INSN_FUNCTION_USAGE. */
   if (CALL_P (insn_info->insn))
-    df_get_call_refs (collection_rec, bb, insn_info,
-		      (is_cond_exec) ? DF_REF_CONDITIONAL : 0);
+    df_get_call_refs (collection_rec, bb, insn_info, flags);
+
+  if (asm_noperands (PATTERN (insn_info->insn)) >= 0)
+    for (unsigned i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+      if (global_regs[i])
+       {
+         /* As with calls, asm statements reference all global regs. */
+         df_ref_record (DF_REF_BASE, collection_rec, regno_reg_rtx[i],
+                        NULL, bb, insn_info, DF_REF_REG_USE, flags);
+         df_ref_record (DF_REF_BASE, collection_rec, regno_reg_rtx[i],
+                        NULL, bb, insn_info, DF_REF_REG_DEF, flags);
+       }
 
   /* Record other defs.  These should be mostly for DF_REF_REGULAR, so
      that a qsort on the defs is unnecessary in most cases.  */
diff --git a/gcc/hard-reg-set.h b/gcc/hard-reg-set.h
index 85541f7..b94ebb3 100644
--- a/gcc/hard-reg-set.h
+++ b/gcc/hard-reg-set.h
@@ -660,6 +660,12 @@ struct target_hard_regs {
      across calls even if we are willing to save and restore them.  */
   HARD_REG_SET x_call_fixed_reg_set;
 
+  /* Contains registers that are fixed use -- i.e. in fixed_reg_set -- but
+     only if they are not merely part of that set because they are global
+     regs.  Global regs that are not otherwise fixed can still take part
+     in register allocation.  */
+  HARD_REG_SET x_fixed_nonglobal_reg_set;
+
   /* Contains 1 for registers that are set or clobbered by calls.  */
   /* ??? Ideally, this would be just call_used_regs plus global_regs, but
      for someone's bright idea to have call_used_regs strictly include
@@ -722,6 +728,8 @@ extern struct target_hard_regs *this_target_hard_regs;
   (this_target_hard_regs->x_fixed_regs)
 #define fixed_reg_set \
   (this_target_hard_regs->x_fixed_reg_set)
+#define fixed_nonglobal_reg_set \
+  (this_target_hard_regs->x_fixed_nonglobal_reg_set)
 #define call_used_regs \
   (this_target_hard_regs->x_call_used_regs)
 #define call_really_used_regs \
diff --git a/gcc/ira.c b/gcc/ira.c
index a38e67e..d383a55 100644
--- a/gcc/ira.c
+++ b/gcc/ira.c
@@ -512,7 +512,7 @@ setup_alloc_regs (bool use_hard_frame_p)
 #ifdef ADJUST_REG_ALLOC_ORDER
   ADJUST_REG_ALLOC_ORDER;
 #endif
-  COPY_HARD_REG_SET (no_unit_alloc_regs, fixed_reg_set);
+  COPY_HARD_REG_SET (no_unit_alloc_regs, fixed_nonglobal_reg_set);
   if (! use_hard_frame_p)
     SET_HARD_REG_BIT (no_unit_alloc_regs, HARD_FRAME_POINTER_REGNUM);
   setup_class_hard_regs ();
diff --git a/gcc/reginfo.c b/gcc/reginfo.c
index ccf53bf..f4dac08 100644
--- a/gcc/reginfo.c
+++ b/gcc/reginfo.c
@@ -449,6 +449,7 @@ init_reg_sets_1 (void)
     }
 
   COPY_HARD_REG_SET (call_fixed_reg_set, fixed_reg_set);
+  COPY_HARD_REG_SET (fixed_nonglobal_reg_set, fixed_reg_set);
 
   /* Preserve global registers if called more than once.  */
   for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6ce2c7e..bc7c93f 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-05-03  Bernd Schmidt  <bschmidt@redhat.com>
+
+	PR rtl-optimization/44281
+	* gcc.target/i386/pr44281.c: New test.
+
 2016-05-03  bin cheng  <bin.cheng@arm.com>
 
 	PR tree-optimization/56541
diff --git a/gcc/testsuite/gcc.target/i386/pr44281.c b/gcc/testsuite/gcc.target/i386/pr44281.c
new file mode 100644
index 0000000..e8e9ede
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr44281.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-options "-std=gnu99 -O2" } */
+/* { dg-final { scan-assembler "salq\[ \\t\]+\\\$8, %rbx" } } */
+
+#include <stdint.h>
+
+register uint64_t global_flag_stack __asm__("rbx");
+
+void push_flag_into_global_reg_var(uint64_t a, uint64_t b) {
+  uint64_t flag = (a==b);
+  global_flag_stack <<= 8;
+  global_flag_stack  |= flag;
+}