From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 30 May 2017 07:40:21 +0000 (+0200)
Subject: backport: re PR rtl-optimization/78378 (wrong code when combining shift + mult +... 
X-Git-Tag: releases/gcc-5.5.0~288
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cdd17c3b486a427de8e92d89472530f277506138;p=thirdparty%2Fgcc.git

backport: re PR rtl-optimization/78378 (wrong code when combining shift + mult + zero_extend)

	Backported from mainline
	2016-11-16  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/78378
	* combine.c (make_extraction): Use force_to_mode for non-{REG,MEM}
	inner only if pos is 0.  Fix up formatting.

	* gcc.c-torture/execute/pr78378.c: New test.

From-SVN: r248623
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7772c3d7749a..0f79e4fe0417 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,12 @@
 2017-05-30  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2016-11-16  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/78378
+	* combine.c (make_extraction): Use force_to_mode for non-{REG,MEM}
+	inner only if pos is 0.  Fix up formatting.
+
 	2016-11-07  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/78227
diff --git a/gcc/combine.c b/gcc/combine.c
index a6c134458582..936aa756eea9 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -7342,6 +7342,7 @@ make_extraction (machine_mode mode, rtx inner, HOST_WIDE_INT pos,
   if (tmode != BLKmode
       && ((pos_rtx == 0 && (pos % BITS_PER_WORD) == 0
 	   && !MEM_P (inner)
+	   && (pos == 0 || REG_P (inner))
 	   && (inner_mode == tmode
 	       || !REG_P (inner)
 	       || TRULY_NOOP_TRUNCATION_MODES_P (tmode, inner_mode)
@@ -7418,10 +7419,9 @@ make_extraction (machine_mode mode, rtx inner, HOST_WIDE_INT pos,
 	}
       else
 	new_rtx = force_to_mode (inner, tmode,
-			     len >= HOST_BITS_PER_WIDE_INT
-			     ? ~(unsigned HOST_WIDE_INT) 0
-			     : ((unsigned HOST_WIDE_INT) 1 << len) - 1,
-			     0);
+				 len >= HOST_BITS_PER_WIDE_INT
+				 ? ~(unsigned HOST_WIDE_INT) 0
+				 : ((unsigned HOST_WIDE_INT) 1 << len) - 1, 0);
 
       /* If this extraction is going into the destination of a SET,
 	 make a STRICT_LOW_PART unless we made a MEM.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 74f7bfdf55d2..78d6ccf89c43 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@
 2017-05-30  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2016-11-16  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/78378
+	* gcc.c-torture/execute/pr78378.c: New test.
+
 	2016-11-07  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/78227
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr78378.c b/gcc/testsuite/gcc.c-torture/execute/pr78378.c
new file mode 100644
index 000000000000..05c1f9c771c1
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr78378.c
@@ -0,0 +1,18 @@
+/* PR rtl-optimization/78378 */
+
+unsigned long long __attribute__ ((noinline, noclone))
+foo (unsigned long long x)
+{
+  x <<= 41;
+  x /= 232;
+  return 1 + (unsigned short) x;
+}
+
+int
+main ()
+{
+  unsigned long long x = foo (1);
+  if (x != 0x2c24)
+    __builtin_abort();
+  return 0;
+}