From e75bcc2ec4f1e7e081ce18713f0a25913ba15340 Mon Sep 17 00:00:00 2001
From: Vladimir Makarov <vmakarov@redhat.com>
Date: Wed, 10 Jul 2019 16:07:10 +0000
Subject: [PATCH 39/39] process_alt_operands: Don't match user defined regs
 only if they are early clobbers

PR target/91102 (aarch64 ICE on Linux kernel with -Os starting with r270266)

2019-07-10  Vladimir Makarov  <vmakarov@redhat.com>

	PR target/91102
	* lra-constraints.c (process_alt_operands): Don't match user
	defined regs only if they are early clobbers.

2019-07-10  Vladimir Makarov  <vmakarov@redhat.com>

	PR target/91102
	* gcc.target/aarch64/pr91102.c: New test.

From-SVN: r273357
Upstream-Status: Backport [https://github.com/gcc-mirror/gcc/commit/613caed2feb9cfc8158308670b59df3d031ec629]
[takondra: dropped conflicting ChangeLog changes]
Signed-off-by: Taras Kondratiuk <takondra@cisco.com>
---
 gcc/lra-constraints.c                      | 17 ++++++++++----
 gcc/testsuite/gcc.target/aarch64/pr91102.c | 26 ++++++++++++++++++++++
 2 files changed, 39 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/aarch64/pr91102.c

diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index cf33da8013e..6382dbf852b 100644
--- a/gcc/lra-constraints.c
+++ b/gcc/lra-constraints.c
@@ -2172,8 +2172,9 @@ process_alt_operands (int only_alternative)
 		    else
 		      {
 			/* Operands don't match.  If the operands are
-			   different user defined explicit hard registers,
-			   then we cannot make them match.  */
+			   different user defined explicit hard
+			   registers, then we cannot make them match
+			   when one is early clobber operand.  */
 			if ((REG_P (*curr_id->operand_loc[nop])
 			     || SUBREG_P (*curr_id->operand_loc[nop]))
 			    && (REG_P (*curr_id->operand_loc[m])
@@ -2192,9 +2193,17 @@ process_alt_operands (int only_alternative)
 				&& REG_P (m_reg)
 				&& HARD_REGISTER_P (m_reg)
 				&& REG_USERVAR_P (m_reg))
-			      break;
+			      {
+				int i;
+				
+				for (i = 0; i < early_clobbered_regs_num; i++)
+				  if (m == early_clobbered_nops[i])
+				    break;
+				if (i < early_clobbered_regs_num
+				    || early_clobber_p)
+				  break;
+			      }
 			  }
-
 			/* Both operands must allow a reload register,
 			   otherwise we cannot make them match.  */
 			if (curr_alt[m] == NO_REGS)
diff --git a/gcc/testsuite/gcc.target/aarch64/pr91102.c b/gcc/testsuite/gcc.target/aarch64/pr91102.c
new file mode 100644
index 00000000000..70b99045a48
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/pr91102.c
@@ -0,0 +1,26 @@
+/* PR target/91102 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+int
+foo (long d, long l)
+{
+  register long e asm ("x1") = d;
+  register long f asm("x2") = l;
+  asm ("" : : "r" (e), "r" (f));
+  return 3;
+}
+
+struct T { int i; int j; };
+union S { long h; struct T t; };
+
+void
+bar (union S b)
+{
+  while (1)
+    {
+      union S c = b;
+      c.t.j++;
+      b.h = foo (b.h, c.h);
+    }
+}
-- 
2.25.1