Fix for PR 91333 - suboptimal register allocation for inline asm

    2020-01-31  Vladimir Makarov  <vmakarov@redhat.com>

            PR rtl-optimization/91333
            * ira-color.c (bucket_allocno_compare_func): Move conflict hard
            reg preferences comparison up.

    2020-01-31  Vladimir Makarov  <vmakarov@redhat.com>

            PR rtl-optimization/91333
            * gcc.target/i386/pr91333.c: New.

gcc/ChangeLog

+2020-01-31  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR rtl-optimization/91333
+	* ira-color.c (bucket_allocno_compare_func): Move conflict hard
+	reg preferences comparison up.
+
 2020-01-31  Richard Sandiford  <richard.sandiford@arm.com>
 
 	* config/aarch64/aarch64.h (TARGET_SVE_BF16): New macro.

gcc/ira-color.c

@@ -2251,6 +2251,11 @@ bucket_allocno_compare_func (const void *v1p, const void *v2p)
   ira_allocno_t t2 = ALLOCNO_COLOR_DATA (a2)->first_thread_allocno;
   int cl1 = ALLOCNO_CLASS (a1), cl2 = ALLOCNO_CLASS (a2);
 
+  /* Push allocnos with minimal conflict_allocno_hard_prefs first.  */
+  pref1 = ALLOCNO_COLOR_DATA (a1)->conflict_allocno_hard_prefs;
+  pref2 = ALLOCNO_COLOR_DATA (a2)->conflict_allocno_hard_prefs;
+  if ((diff = pref1 - pref2) != 0)
+    return diff;
   freq1 = ALLOCNO_COLOR_DATA (t1)->thread_freq;
   freq2 = ALLOCNO_COLOR_DATA (t2)->thread_freq;
   if ((diff = freq1 - freq2) != 0)
@@ -2276,11 +2281,6 @@ bucket_allocno_compare_func (const void *v1p, const void *v2p)
   a2_num = ALLOCNO_COLOR_DATA (a2)->available_regs_num;
   if ((diff = a2_num - a1_num) != 0)
     return diff;
-  /* Push allocnos with minimal conflict_allocno_hard_prefs first.  */
-  pref1 = ALLOCNO_COLOR_DATA (a1)->conflict_allocno_hard_prefs;
-  pref2 = ALLOCNO_COLOR_DATA (a2)->conflict_allocno_hard_prefs;
-  if ((diff = pref1 - pref2) != 0)
-    return diff;
   return ALLOCNO_NUM (a2) - ALLOCNO_NUM (a1);
 }
 

gcc/testsuite/ChangeLog

+2020-01-31  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR rtl-optimization/91333
+	* gcc.target/i386/pr91333.c: New.
+
 2020-01-31  David Malcolm  <dmalcolm@redhat.com>
 
 	PR analyzer/93379

gcc/testsuite/gcc.target/i386/pr91333.c

+/* { dg-do compile { target x86_64-*-* } } */
+/* { dg-options "-O2 -mavx" } */
+/* { dg-final { scan-assembler-times "vmovapd" 2 } } */
+
+static inline double g (double x){
+  asm volatile ("" : "+x" (x));
+  return x;
+}
+static inline double f (double a, double b){
+  return g (g (a) + g (b));
+}
+double h (double a, double b){
+  return f (f (a, a), f (b, b));
+}