re PR rtl-optimization/89225 (LRA hang on ppc64le compiling glibc starting with r268404)

2019-02-06  Vladimir Makarov  <vmakarov@redhat.com>

	PR rtl-optimization/89225
	* lra-constaints.c (simplify_operand_subreg): Add subreg mode
	sizes check.

2019-02-06  Vladimir Makarov  <vmakarov@redhat.com>

	PR rtl-optimization/89225
	* gcc.target/powerpc/pr89225.c: New.

From-SVN: r268597

gcc/ChangeLog

+2019-02-06  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR rtl-optimization/89225
+	* lra-constaints.c (simplify_operand_subreg): Add subreg mode
+	sizes check.
+
 2019-02-06  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* config/i386/i386.c (ix86_expand_prologue): Emit a memory blockage

gcc/lra-constraints.c

@@ -1533,9 +1533,12 @@ simplify_operand_subreg (int nop, machine_mode reg_mode)
 	     a word.
 
 	     If valid memory becomes invalid after subreg elimination
-	     we still have to reload memory.
+	     and address might be different we still have to reload
+	     memory.
 	  */
-	  if ((! addr_was_valid || addr_is_valid)
+	  if ((! addr_was_valid
+	       || addr_is_valid
+	       || known_eq (GET_MODE_SIZE (mode), GET_MODE_SIZE (innermode)))
 	      && !(maybe_ne (GET_MODE_PRECISION (mode),
 			     GET_MODE_PRECISION (innermode))
 		   && known_le (GET_MODE_SIZE (mode), UNITS_PER_WORD)

gcc/testsuite/ChangeLog

+2019-02-06  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR rtl-optimization/89225
+	* gcc.target/powerpc/pr89225.c: New.
+
 2019-02-06  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gnat.dg/opt76.adb: New test.

gcc/testsuite/gcc.target/powerpc/pr89225.c

+/* { dg-do compile  { target { powerpc*-*-* && lp64 } } } */
+/* { dg-options "-O2 -fstack-protector-strong -mlong-double-128" } */
+
+extern long double foo (long double);
+extern double bar (double);
+typedef long long int64_t;
+typedef unsigned long long uint64_t;
+typedef union { int64_t i[2]; long double x; double d[2]; } mynumber;
+static const double t512 = 0x1p512, tm256 = 0x1p-256, two54 = 0x1p54, twom54 = 0x1p-54;
+
+long double
+foo (long double x)
+{
+  static const long double big = 134217728.0, big1 = 134217729.0;
+  long double t, s, i;
+  mynumber a, c;
+  uint64_t k, l;
+  int64_t m, n;
+  double d;
+
+  a.x = x;
+  k = a.i[0] & 0x7fffffffffffffffL;
+
+  if (k > 0x000fffff00000000L && k < 0x7ff0000000000000L)
+    {
+      if (x < 0)
+	return (big1 - big1) / (big - big);
+      l = (k & 0x001fffffffffffffL) | 0x3fe0000000000000L;
+      if ((a.i[1] & 0x7fffffffffffffffL) != 0)
+	{
+	  n = (int64_t) ((l - k) * 2) >> 53;
+	  m = (a.i[1] >> 52) & 0x7ff;
+	  if (m == 0)
+	    {
+	      a.d[1] *= two54;
+	      m = ((a.i[1] >> 52) & 0x7ff) - 54;
+	    }
+	  m += n;
+	  if (m > 0)
+	    a.i[1] = (a.i[1] & 0x800fffffffffffffL) | (m << 52);
+	  else if (m <= -54)
+	    {
+	      a.i[1] &= 0x8000000000000000L;
+	    }
+	  else
+	    {
+	      m += 54;
+	      a.i[1] = (a.i[1] & 0x800fffffffffffffL) | (m << 52);
+	      a.d[1] *= twom54;
+	    }
+	}
+      a.i[0] = l;
+      s = a.x;
+      d = bar (a.d[0]);
+      c.i[0] = 0x2000000000000000L + ((k & 0x7fe0000000000000L) >> 1);
+      c.i[1] = 0;
+      i = d;
+      t = 0.5L * (i + s / i);
+      i = 0.5L * (t + s / t);
+      return c.x * i;
+    }
+  else
+    {
+      if (k >= 0x7ff0000000000000L)
+
+	return x * x + x;
+      if (x == 0)
+	return x;
+      if (x < 0)
+	return (big1 - big1) / (big - big);
+      return tm256 * foo (x * t512);
+    }
+}