tcg/arm: Try pc-relative addresses for movi

Backports commit 9c39b94f1448770e7e573e9516d2483816785d1b from qemu
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Richard Henderson 2018-03-03 17:13:29 -05:00 committed by Lioncash
parent a5133ccaa1
commit c99edca63b
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@ -427,13 +427,9 @@ static inline void tcg_out_dat_imm(TCGContext *s,
static void tcg_out_movi32(TCGContext *s, int cond, int rd, uint32_t arg)
{
int rot, opc, rn;
int rot, opc, rn, diff;
/* For armv7, make sure not to use movw+movt when mov/mvn would do.
Speed things up by only checking when movt would be required.
Prior to armv7, have one go at fully rotated immediates before
doing the decomposition thing below. */
if (!use_armv7_instructions || (arg & 0xffff0000)) {
/* Check a single MOV/MVN before anything else. */
rot = encode_imm(arg);
if (rot >= 0) {
tcg_out_dat_imm(s, cond, ARITH_MOV, rd, 0,
@ -446,6 +442,24 @@ static void tcg_out_movi32(TCGContext *s, int cond, int rd, uint32_t arg)
rotl(~arg, rot) | (rot << 7));
return;
}
/* Check for a pc-relative address. This will usually be the TB,
or within the TB, which is immediately before the code block. */
diff = arg - ((intptr_t)s->code_ptr + 8);
if (diff >= 0) {
rot = encode_imm(diff);
if (rot >= 0) {
tcg_out_dat_imm(s, cond, ARITH_ADD, rd, TCG_REG_PC,
rotl(diff, rot) | (rot << 7));
return;
}
} else {
rot = encode_imm(-diff);
if (rot >= 0) {
tcg_out_dat_imm(s, cond, ARITH_SUB, rd, TCG_REG_PC,
rotl(-diff, rot) | (rot << 7));
return;
}
}
/* Use movw + movt. */