From: Kwok Cheung Yeung <kcy@codesourcery.com>
Date: Sun, 10 Nov 2019 18:22:38 +0000 (+0000)
Subject: [LRA] Do not use eliminable registers for spilling
X-Git-Tag: misc/cutover-git~1389
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4b77a3806c4f2e27d149da326a689286043e433c;p=thirdparty%2Fgcc.git

[LRA] Do not use eliminable registers for spilling

The liveness of eliminable hard registers is not tracked by LRA between
basic blocks, so they should not be used as spill registers as LRA may
decide to allocate them to pseudos while the spilled value is still live.

2019-11-10  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* lra-spills.c (assign_spill_hard_regs): Do not spill into
	registers in eliminable_regset.

From-SVN: r278024
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 02b24d3b4b19..8b7ed6358c33 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2019-11-10  Kwok Cheung Yeung  <kcy@codesourcery.com>
+
+	* lra-spills.c (assign_spill_hard_regs): Do not spill into
+	registers in eliminable_regset.
+
 2019-11-10  Jan Hubicka  <hubicka@ucw.cz>
 
 	* ipa-inline.c (compute_uninlined_call_time,
diff --git a/gcc/lra-spills.c b/gcc/lra-spills.c
index 0068e52ace1e..54f76ccf8644 100644
--- a/gcc/lra-spills.c
+++ b/gcc/lra-spills.c
@@ -283,6 +283,8 @@ assign_spill_hard_regs (int *pseudo_regnos, int n)
       for (k = 0; k < spill_class_size; k++)
 	{
 	  hard_regno = ira_class_hard_regs[spill_class][k];
+	  if (TEST_HARD_REG_BIT (eliminable_regset, hard_regno))
+	    continue;
 	  if (! overlaps_hard_reg_set_p (conflict_hard_regs, mode, hard_regno))
 	    break;
 	}