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* [PATCH] aarch64: Do not alter value on a force_reg returned rtx expanding __jcvt
@ 2020-09-21 10:31 Andrea Corallo
  2020-09-21 10:58 ` Richard Sandiford
  0 siblings, 1 reply; 5+ messages in thread
From: Andrea Corallo @ 2020-09-21 10:31 UTC (permalink / raw)
  To: gcc-patches; +Cc: kyrylo.tkachov, richard.earnshaw, nd

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Hi all,

From the `force_reg` description comment I see the returned register
should not be modified, thus IIUC should not be used as a GEN_FCN
target.

Assuming my interpretation is correct this fix this case inside
`aarch64_general_expand_builtin` while expanding expanding the
`__jcvt` intrinsic.  If is not the case please discard.

Regtested and bootsraped on aarch64-linux-gnu.

  Andrea


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From 403ad66b8f9c108d7f38b406ed1afcb603b7e25f Mon Sep 17 00:00:00 2001
From: Andrea Corallo <andrea.corallo@arm.com>
Date: Thu, 17 Sep 2020 17:17:52 +0100
Subject: [PATCH] aarch64: Do not alter value on a force_reg returned rtx
 expanding __jcvt

2020-09-17  Andrea Corallo  <andrea.corallo@arm.com>

	* config/aarch64/aarch64-builtins.c
	(aarch64_general_expand_builtin): Use expand machinery not to
	alter the value of an rtx returned by force_reg.
---
 gcc/config/aarch64/aarch64-builtins.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/gcc/config/aarch64/aarch64-builtins.c b/gcc/config/aarch64/aarch64-builtins.c
index 4f33dd936c7..b787719cf5e 100644
--- a/gcc/config/aarch64/aarch64-builtins.c
+++ b/gcc/config/aarch64/aarch64-builtins.c
@@ -2128,14 +2128,14 @@ aarch64_general_expand_builtin (unsigned int fcode, tree exp, rtx target,
       return target;
 
     case AARCH64_JSCVT:
-      arg0 = CALL_EXPR_ARG (exp, 0);
-      op0 = force_reg (DFmode, expand_normal (arg0));
-      if (!target)
-	target = gen_reg_rtx (SImode);
-      else
-	target = force_reg (SImode, target);
-      emit_insn (GEN_FCN (CODE_FOR_aarch64_fjcvtzs) (target, op0));
-      return target;
+      {
+	expand_operand ops[2];
+	create_output_operand (&ops[0], target, SImode);
+	op0 = expand_normal (CALL_EXPR_ARG (exp, 0));
+	create_input_operand (&ops[1], op0, DFmode);
+	expand_insn (CODE_FOR_aarch64_fjcvtzs, 2, ops);
+	return ops[0].value;
+      }
 
     case AARCH64_SIMD_BUILTIN_FCMLA_LANEQ0_V2SF:
     case AARCH64_SIMD_BUILTIN_FCMLA_LANEQ90_V2SF:
-- 
2.17.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2020-09-24  9:51 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-09-21 10:31 [PATCH] aarch64: Do not alter value on a force_reg returned rtx expanding __jcvt Andrea Corallo
2020-09-21 10:58 ` Richard Sandiford
2020-09-21 11:00   ` Kyrylo Tkachov
2020-09-21 12:13     ` Andrea Corallo
2020-09-24  9:50       ` Andrea Corallo

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