From: Jakub Jelinek <jakub@redhat.com>
Date: Fri, 22 Jun 2018 21:29:24 +0000 (+0200)
Subject: backport: re PR target/85945 (ICE in resolve_subreg_use, at lower-subreg.c:751)
X-Git-Tag: releases/gcc-7.4.0~322
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=eb989a7c141aaba0926bec114cc3f80b449fea63;p=thirdparty%2Fgcc.git

backport: re PR target/85945 (ICE in resolve_subreg_use, at lower-subreg.c:751)

	Backported from mainline
	2018-06-14  Jakub Jelinek  <jakub@redhat.com>

	PR target/85945
	* lower-subreg.c (find_decomposable_subregs): Don't decompose float
	subregs of multi-word pseudos unless the float mode has word size.

	* gcc.c-torture/compile/pr85945.c: New test.

From-SVN: r261967
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 28fe85fdfc2b..739717cea2a0 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,12 @@
 2018-06-22  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2018-06-14  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/85945
+	* lower-subreg.c (find_decomposable_subregs): Don't decompose float
+	subregs of multi-word pseudos unless the float mode has word size.
+
 	2018-06-04  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/86025
diff --git a/gcc/lower-subreg.c b/gcc/lower-subreg.c
index a4dcec51bb56..b1e2e287e154 100644
--- a/gcc/lower-subreg.c
+++ b/gcc/lower-subreg.c
@@ -490,7 +490,16 @@ find_decomposable_subregs (rtx *loc, enum classify_move_insn *pcmi)
 	     were the same number and size of pieces.  Hopefully this
 	     doesn't happen much.  */
 
-	  if (outer_words == 1 && inner_words > 1)
+	  if (outer_words == 1
+	      && inner_words > 1
+	      /* Don't allow to decompose floating point subregs of
+		 multi-word pseudos if the floating point mode does
+		 not have word size, because otherwise we'd generate
+		 a subreg with that floating mode from a different
+		 sized integral pseudo which is not allowed by
+		 validate_subreg.  */
+	      && (!FLOAT_MODE_P (GET_MODE (x))
+		  || outer_size == UNITS_PER_WORD))
 	    {
 	      bitmap_set_bit (decomposable_context, regno);
 	      iter.skip_subrtxes ();
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e0d1544a7a4a..f8f71ea5da00 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -6,6 +6,11 @@
 	PR c++/85662
 	* g++.dg/ext/offsetof3.C: New test.
 
+	2018-06-14  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/85945
+	* gcc.c-torture/compile/pr85945.c: New test.
+
 	2018-06-04  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/86025
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr85945.c b/gcc/testsuite/gcc.c-torture/compile/pr85945.c
new file mode 100644
index 000000000000..93b2023f25cb
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr85945.c
@@ -0,0 +1,16 @@
+/* PR target/85945 */
+
+typedef float V __attribute__((vector_size(16)));
+union U { V v; float f[4]; };
+int f;
+float g[4];
+
+void
+foo (void)
+{
+  V d;
+  union U i;
+  i.v = d;
+  for (f = 0; f < 4; f++)
+    g[f] = i.f[f];
+}