[gcc(refs/vendors/redhat/heads/gcc-8-branch)] re PR rtl-optimization/93088 (Compile time hog on gcc/testsuite/gcc.target/i386/pr56348.c w/ -O3 -fu

[Jakub Jelinek]

https://gcc.gnu.org/g:c4cfb11a99885a73ad5dbf58f9030d13ceebf4b5

commit c4cfb11a99885a73ad5dbf58f9030d13ceebf4b5
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Feb 14 15:34:43 2020 +0100

    re PR rtl-optimization/93088 (Compile time hog on gcc/testsuite/gcc.target/i386/pr56348.c w/ -O3 -funroll-loops -fno-tree-dominator-opts -fno-tree-vrp)
    
            PR rtl-optimization/93088
            * loop-iv.c (find_single_def_src): Punt after looking through
            128 reg copies for regs with single definitions.  Move definitions
            to first uses.
    
            * gcc.target/i386/pr93088.c: New test.

Diff:
---
 gcc/ChangeLog                           |  6 ++++++
 gcc/loop-iv.c                           | 15 +++++++--------
 gcc/testsuite/ChangeLog                 |  5 +++++
 gcc/testsuite/gcc.target/i386/pr93088.c |  5 +++++
 4 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 704d01f2565..05cbf6ec009 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,12 @@
 2020-02-14  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2020-01-02  Jakub Jelinek  <jakub@redhat.com>
+
+	PR ipa/93087
+	* predict.c (compute_function_frequency): Don't call
+	warn_function_cold on functions that already have cold attribute.
+
 	2019-12-14  Jakub Jelinek  <jakub@redhat.com>
 
 	PR ipa/92357
diff --git a/gcc/loop-iv.c b/gcc/loop-iv.c
index 8f476819728..fb09e0f6e54 100644
--- a/gcc/loop-iv.c
+++ b/gcc/loop-iv.c
@@ -1380,24 +1380,23 @@ simple_rhs_p (rtx rhs)
 static rtx
 find_single_def_src (unsigned int regno)
 {
-  df_ref adef;
-  rtx set, src;
+  rtx src = NULL_RTX;
 
-  for (;;)
+  /* Don't look through unbounded number of single definition REG copies,
+     there might be loops for sources with uninitialized variables.  */
+  for (int cnt = 0; cnt < 128; cnt++)
     {
-      rtx note;
-      adef = DF_REG_DEF_CHAIN (regno);
+      df_ref adef = DF_REG_DEF_CHAIN (regno);
       if (adef == NULL || DF_REF_NEXT_REG (adef) != NULL
 	  || DF_REF_IS_ARTIFICIAL (adef))
 	return NULL_RTX;
 
-      set = single_set (DF_REF_INSN (adef));
+      rtx set = single_set (DF_REF_INSN (adef));
       if (set == NULL || !REG_P (SET_DEST (set))
 	  || REGNO (SET_DEST (set)) != regno)
 	return NULL_RTX;
 
-      note = find_reg_equal_equiv_note (DF_REF_INSN (adef));
-
+      rtx note = find_reg_equal_equiv_note (DF_REF_INSN (adef));
       if (note && function_invariant_p (XEXP (note, 0)))
 	{
 	  src = XEXP (note, 0);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f6e4ee150e5..98a16e919ef 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@
 2020-02-14  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2020-01-02  Jakub Jelinek  <jakub@redhat.com>
+
+	PR ipa/93087
+	* c-c++-common/cold-1.c: New test.
+
 	2019-12-26  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/92438
diff --git a/gcc/testsuite/gcc.target/i386/pr93088.c b/gcc/testsuite/gcc.target/i386/pr93088.c
new file mode 100644
index 00000000000..dc986cfaa80
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr93088.c
@@ -0,0 +1,5 @@
+/* PR rtl-optimization/93088 */
+/* { dg-do compile } */
+/* { dg-options "-O3 -funroll-loops -fno-tree-dominator-opts -fno-tree-vrp -w" } */
+
+#include "pr56348.c"