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authorRichard Henderson <rth@twiddle.net>2013-03-27 14:37:42 -0400
committerRichard Henderson <rth@twiddle.net>2013-04-05 13:35:41 -0500
commit78c9f7c5b09408b4cac69a4fee97a118c8a89f6c (patch)
treeb98cf05a69b5cbff780e884e4b5964f8ac1d56fc /tcg/s390
parent0db921e6d8660a2491c173a2821e30924018d4bb (diff)
tcg-s390: Use all 20 bits of the offset in tcg_out_mem
This can save one insn, if the constant has any bits in 32-63 set, but no bits in 21-31 set. It never results in more insns. Signed-off-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'tcg/s390')
-rw-r--r--tcg/s390/tcg-target.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/tcg/s390/tcg-target.c b/tcg/s390/tcg-target.c
index 22927dfa26..8e660b318d 100644
--- a/tcg/s390/tcg-target.c
+++ b/tcg/s390/tcg-target.c
@@ -748,10 +748,11 @@ static void tcg_out_mem(TCGContext *s, S390Opcode opc_rx, S390Opcode opc_rxy,
tcg_target_long ofs)
{
if (ofs < -0x80000 || ofs >= 0x80000) {
- /* Combine the low 16 bits of the offset with the actual load insn;
- the high 48 bits must come from an immediate load. */
- tcg_out_movi(s, TCG_TYPE_PTR, TCG_TMP0, ofs & ~0xffff);
- ofs &= 0xffff;
+ /* Combine the low 20 bits of the offset with the actual load insn;
+ the high 44 bits must come from an immediate load. */
+ tcg_target_long low = ((ofs & 0xfffff) ^ 0x80000) - 0x80000;
+ tcg_out_movi(s, TCG_TYPE_PTR, TCG_TMP0, ofs - low);
+ ofs = low;
/* If we were already given an index register, add it in. */
if (index != TCG_REG_NONE) {