From 8cc857f9490dd71c311b529c4284f54a597e97bd Mon Sep 17 00:00:00 2001
From: Uros Bizjak <ubizjak@gmail.com>
Date: Sun, 22 Oct 2017 20:05:17 +0200
Subject: [PATCH] re PR rtl-optimization/82628 (wrong code at -Os on
 x86_64-linux-gnu in the 32-bit mode)

	PR target/82628
	* config/i386/i386.md (cmp<dwi>_doubleword): New pattern.
	* config/i386/i386.c (ix86_expand_branch) <case E_TImode>:
	Expand with cmp<dwi>_doubleword.

testsuite/ChangeLog:

	PR target/82628
	* gcc.dg/torture/pr82628.c: New test.


Co-Authored-By: Jakub Jelinek <jakub@redhat.com>

From-SVN: r253985
---
 gcc/config/i386/i386.c                  | 26 +++++++------------
 gcc/config/i386/i386.md                 | 22 +++++++++++++++-
 gcc/testsuite/ChangeLog                 |  6 +++++
 gcc/testsuite/gcc.target/i386/pr82628.c | 34 +++++++++++++++++++++++++
 4 files changed, 70 insertions(+), 18 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr82628.c

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index fb0b7e71469..5abd4d8ab25 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -22357,33 +22357,25 @@ ix86_expand_branch (enum rtx_code code, rtx op0, rtx op1, rtx label)
 	switch (code)
 	  {
 	  case LE: case LEU: case GT: case GTU:
-	    std::swap (lo[0], lo[1]);
-	    std::swap (hi[0], hi[1]);
+	    std::swap (op0, op1);
 	    code = swap_condition (code);
 	    /* FALLTHRU */
 
 	  case LT: case LTU: case GE: case GEU:
 	    {
-	      rtx (*cmp_insn) (rtx, rtx);
-	      rtx (*sbb_insn) (rtx, rtx, rtx);
+	      rtx (*cmp_insn) (rtx, rtx, rtx);
 
 	      if (TARGET_64BIT)
-		cmp_insn = gen_cmpdi_1, sbb_insn = gen_subdi3_carry_ccgz;
+		cmp_insn = gen_cmpti_doubleword;
 	      else
-		cmp_insn = gen_cmpsi_1, sbb_insn = gen_subsi3_carry_ccgz;
-
-	      if (!nonimmediate_operand (lo[0], submode))
-		lo[0] = force_reg (submode, lo[0]);
-	      if (!x86_64_general_operand (lo[1], submode))
-		lo[1] = force_reg (submode, lo[1]);
+		cmp_insn = gen_cmpdi_doubleword;
 
-	      if (!register_operand (hi[0], submode))
-		hi[0] = force_reg (submode, hi[0]);
-	      if (!x86_64_general_operand (hi[1], submode))
-		hi[1] = force_reg (submode, hi[1]);
+	      if (!register_operand (op0, mode))
+		op0 = force_reg (mode, op0);
+	      if (!x86_64_hilo_general_operand (op1, mode))
+		op1 = force_reg (mode, op1);
 
-	      emit_insn (cmp_insn (lo[0], lo[1]));
-	      emit_insn (sbb_insn (gen_rtx_SCRATCH (submode), hi[0], hi[1]));
+	      emit_insn (cmp_insn (gen_rtx_SCRATCH (mode), op0, op1));
 
 	      tmp = gen_rtx_REG (CCGZmode, FLAGS_REG);
 
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index fcb3edddf82..1fc4a38b82c 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -1273,6 +1273,26 @@
 	(compare:CC (match_operand:SWI48 0 "nonimmediate_operand")
 		    (match_operand:SWI48 1 "<general_operand>")))])
 
+(define_insn_and_split "cmp<dwi>_doubleword"
+  [(set (reg:CCGZ FLAGS_REG)
+	(compare:CCGZ
+	  (match_operand:<DWI> 1 "register_operand" "0")
+	  (match_operand:<DWI> 2 "x86_64_hilo_general_operand" "ro<di>")))
+   (clobber (match_scratch:<DWI> 0 "=r"))]
+  ""
+  "#"
+  "reload_completed"
+  [(set (reg:CC FLAGS_REG)
+	(compare:CC (match_dup 1) (match_dup 2)))
+   (parallel [(set (reg:CCGZ FLAGS_REG)
+		   (compare: CCGZ
+		     (match_dup 4)
+		     (plus:DWIH
+		       (ltu:DWIH (reg:CC FLAGS_REG) (const_int 0))
+		       (match_dup 5))))
+	      (clobber (match_dup 3))])]
+  "split_double_mode (<DWI>mode, &operands[0], 3, &operands[0], &operands[3]);")
+
 (define_insn "*cmp<mode>_ccno_1"
   [(set (reg FLAGS_REG)
 	(compare (match_operand:SWI 0 "nonimmediate_operand" "<r>,?m<r>")
@@ -6891,7 +6911,7 @@
    (set_attr "pent_pair" "pu")
    (set_attr "mode" "SI")])
 
-(define_insn "sub<mode>3_carry_ccgz"
+(define_insn "*sub<mode>3_carry_ccgz"
   [(set (reg:CCGZ FLAGS_REG)
 	(compare:CCGZ
 	  (match_operand:DWIH 1 "register_operand" "0")
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a69c8518c36..493b361c8bf 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2017-10-22  Uros Bizjak  <ubizjak@gmail.com>
+	    Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/82628
+	* gcc.dg/torture/pr82628.c: New test.
+
 2017-10-22  Igor Tsimbalist  <igor.v.tsimbalist@intel.com>
 
 	* c-c++-common/attr-nocf-check-1a.c: Remove test.
diff --git a/gcc/testsuite/gcc.target/i386/pr82628.c b/gcc/testsuite/gcc.target/i386/pr82628.c
new file mode 100644
index 00000000000..d7135220485
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr82628.c
@@ -0,0 +1,34 @@
+/* { dg-do run { target ia32 } } */
+/* { dg-options "-Os" } */
+
+void
+__attribute__ ((noipa))
+foo (const char *x)
+{
+  asm volatile ("" : "+g" (x) : : "memory");
+  if (x)
+    __builtin_abort ();
+}
+
+int a, b = 1;
+
+int
+main ()
+{
+  while (1)
+    {
+      unsigned long long d = 18446744073709551615UL;
+      while (1)
+	{
+	  int e = b;
+	  while (d < 2)
+	    foo ("0");
+	  if (a)
+	    d++;
+	  if (b)
+	    break;
+	}
+      break;
+    }
+  return 0;
+}
-- 
2.30.2