pr45678-2.c ICEs for msp430-elf with -mlarge, because an alignment of
POINTER_SIZE is attempted. POINTER_SIZE with -mlarge is 20-bits, so further
code in the middle-end that expects this to be a power or 2 causes odd
alignments to be set, in this case eventually resulting in an ICE.
The test ICEs on gcc-7-branch, gcc-8-branch, and current trunk. It
successfully builds on gcc-6-branch.
The failure is caused by r235172.
Successfully bootstrapped and regtested the attached patch for
x86-64-pc-linux-gnu, and msp430-elf with -mlarge, on trunk.
Ok for gcc-7-branch, gcc-8-branch and trunk?
>From e655a518a06a848dc398504f28272750e1a2be9f Mon Sep 17 00:00:00 2001
From: Jozef Lawrynowicz <jozefl.open...@gmail.com>
Date: Tue, 13 Mar 2018 11:25:56 +0000
Subject: [PATCH] When aligning to POINTER_SIZE, round alignment to largest
power of 2 that is <= POINTER_SIZE
PR middle-end/86705
* gcc/cfgexpand.c (set_parm_rtl): Before using POINTER_SIZE as an
alignment value, round it to the largest power of 2 less than or equal
to itself.
(expand_one_ssa_partition): Likewise.
(expand_one_var): Likewise.
---
gcc/cfgexpand.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index d6e3c38..a56db7a 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -1258,9 +1258,12 @@ set_parm_rtl (tree parm, rtx x)
pointer. ??? We've got a pseudo for sure here, do we
actually dynamically allocate its spilling area if needed?
??? Isn't it a problem when POINTER_SIZE also exceeds
- MAX_SUPPORTED_STACK_ALIGNMENT, as on cris and lm32? */
+ MAX_SUPPORTED_STACK_ALIGNMENT, as on cris and lm32?
+ POINTER_SIZE may not be a power of 2 e.g. for msp430-elf with the large
+ data model, so align to the largest power of 2 that is
+ <= POINTER_SIZE. */
if (align > MAX_SUPPORTED_STACK_ALIGNMENT)
- align = POINTER_SIZE;
+ align = (unsigned)1 << floor_log2 (POINTER_SIZE);
record_alignment_for_reg_var (align);
}
@@ -1381,7 +1384,7 @@ expand_one_ssa_partition (tree var)
/* If the variable alignment is very large we'll dynamicaly allocate
it, which means that in-frame portion is just a pointer. */
if (align > MAX_SUPPORTED_STACK_ALIGNMENT)
- align = POINTER_SIZE;
+ align = (unsigned)1 << floor_log2 (POINTER_SIZE);
record_alignment_for_reg_var (align);
@@ -1608,7 +1611,7 @@ expand_one_var (tree var, bool toplevel, bool really_expand)
/* If the variable alignment is very large we'll dynamicaly allocate
it, which means that in-frame portion is just a pointer. */
if (align > MAX_SUPPORTED_STACK_ALIGNMENT)
- align = POINTER_SIZE;
+ align = (unsigned)1 << floor_log2 (POINTER_SIZE);
}
record_alignment_for_reg_var (align);
--
2.7.4
