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Re: [PATCH][AArch64] Simplify aarch64_can_eliminate
- From: Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>, James Greenhalgh <James dot Greenhalgh at arm dot com>
- Cc: nd <nd at arm dot com>, Richard Earnshaw <Richard dot Earnshaw at arm dot com>
- Date: Tue, 15 Aug 2017 16:25:06 +0000
- Subject: Re: [PATCH][AArch64] Simplify aarch64_can_eliminate
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From: Wilco Dijkstra
Sent: 07 August 2017 15:13
To: GCC Patches; James Greenhalgh
Cc: nd; Richard Earnshaw
Subject: [PATCH][AArch64] Simplify aarch64_can_eliminate
Simplify aarch64_can_eliminate - if we need a frame pointer, we must
eliminate to HARD_FRAME_POINTER_REGNUM. Rather than hardcoding all
combinations from the ELIMINABLE_REGS list, just do the correct check.
ChangeLog:
2017-08-07 Wilco Dijkstra <wdijkstr@arm.com>
gcc/
* config/aarch64/aarch64.c (aarch64_can_eliminate): Simplify logic.
--
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 9463edf63ffe770062b4120fada090e20c93a269..fbb4244cb58d2a25203aa27342c2f7988c30bd98 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -5858,26 +5858,12 @@ aarch64_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x,
}
static bool
-aarch64_can_eliminate (const int from, const int to)
+aarch64_can_eliminate (const int from ATTRIBUTE_UNUSED, const int to)
{
- /* If we need a frame pointer, we must eliminate FRAME_POINTER_REGNUM into
- HARD_FRAME_POINTER_REGNUM and not into STACK_POINTER_REGNUM. */
-
+ /* If we need a frame pointer, ARG_POINTER_REGNUM and FRAME_POINTER_REGNUM
+ can only eliminate to HARD_FRAME_POINTER_REGNUM. */
if (frame_pointer_needed)
- {
- if (from == ARG_POINTER_REGNUM && to == HARD_FRAME_POINTER_REGNUM)
- return true;
- if (from == ARG_POINTER_REGNUM && to == STACK_POINTER_REGNUM)
- return false;
- if (from == FRAME_POINTER_REGNUM && to == STACK_POINTER_REGNUM
- && !cfun->calls_alloca)
- return true;
- if (from == FRAME_POINTER_REGNUM && to == HARD_FRAME_POINTER_REGNUM)
- return true;
-
- return false;
- }
-
+ return to == HARD_FRAME_POINTER_REGNUM;
return true;
}