From 14c8e213350820ffc12ac6b8528c81732e7b6a90 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Mon, 8 Nov 2004 11:18:16 -0800 Subject: [PATCH] expmed.c (extract_force_align_mem_bit_field): Correct handling at the end of a page. * expmed.c (extract_force_align_mem_bit_field): Correct handling at the end of a page. From-SVN: r90288 --- gcc/ChangeLog | 5 +++++ gcc/expmed.c | 16 ++++++++++++---- 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index da58911..3e43541 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2004-11-08 Richard Henderson + + * expmed.c (extract_force_align_mem_bit_field): Correct handling at + the end of a page. + 2004-11-08 Kazu Hirata * sched-deps.c (add_insn_mem_dependence): Make it static. diff --git a/gcc/expmed.c b/gcc/expmed.c index a108efa..191df72 100644 --- a/gcc/expmed.c +++ b/gcc/expmed.c @@ -1891,11 +1891,16 @@ extract_force_align_mem_bit_field (rtx op0, unsigned HOST_WIDE_INT bitsize, if (STRICT_ALIGNMENT) { base = plus_constant (XEXP (op0, 0), bitpos / BITS_PER_UNIT); - base = force_operand (base, NULL); bitpos %= BITS_PER_UNIT; - /* Force alignment of the address; load two sequential values. */ - a1 = expand_simple_binop (Pmode, AND, base, + /* We load two values to be concatenate. There's an edge condition + that bears notice -- an aligned value at the end of a page can + only load one value lest we segfault. So the two values we load + are at "base & -size" and "(base + size - 1) & -size". If base + is unaligned, the addresses will be aligned and sequential; if + base is aligned, the addresses will both be equal to base. */ + + a1 = expand_simple_binop (Pmode, AND, force_operand (base, NULL), GEN_INT (-(HOST_WIDE_INT)m_size), NULL, true, OPTAB_LIB_WIDEN); mark_reg_pointer (a1, m_bitsize); @@ -1903,7 +1908,10 @@ extract_force_align_mem_bit_field (rtx op0, unsigned HOST_WIDE_INT bitsize, set_mem_align (v1, m_bitsize); v1 = force_reg (mode, validize_mem (v1)); - a2 = plus_constant (a1, GET_MODE_SIZE (mode)); + a2 = plus_constant (base, GET_MODE_SIZE (mode) - 1); + a2 = expand_simple_binop (Pmode, AND, force_operand (a2, NULL), + GEN_INT (-(HOST_WIDE_INT)m_size), + NULL, true, OPTAB_LIB_WIDEN); v2 = gen_rtx_MEM (mode, a2); set_mem_align (v2, m_bitsize); v2 = force_reg (mode, validize_mem (v2)); -- 2.7.4