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tcg-s390: Use all 20 bits of the offset in tcg_out_mem

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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>
This commit is contained in:
Richard Henderson 2013-03-27 14:37:42 -04:00
parent 0db921e6d8
commit 78c9f7c5b0
1 changed files with 5 additions and 4 deletions
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9
tcg/s390/tcg-target.c
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@ -748,10 +748,11 @@ static void tcg_out_mem(TCGContext *s, S390Opcode opc_rx, S390Opcode opc_rxy,
tcg_target_long ofs) tcg_target_long ofs)
{ {
if (ofs < -0x80000 || ofs >= 0x80000) { if (ofs < -0x80000 || ofs >= 0x80000) {
/* Combine the low 16 bits of the offset with the actual load insn; /* Combine the low 20 bits of the offset with the actual load insn;
the high 48 bits must come from an immediate load. */ the high 44 bits must come from an immediate load. */
tcg_out_movi(s, TCG_TYPE_PTR, TCG_TMP0, ofs & ~0xffff); tcg_target_long low = ((ofs & 0xfffff) ^ 0x80000) - 0x80000;
ofs &= 0xffff; 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 we were already given an index register, add it in. */
if (index != TCG_REG_NONE) { if (index != TCG_REG_NONE) {