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x86: Generate BMI2 shifts and rotates, if available.

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Contributed by Peter Cawley.
This commit is contained in:
Mike Pall
2016-03-28 23:05:20 +02:00
parent 6801e7165c
commit 892887e584
5 changed files with 51 additions and 7 deletions
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28
src/lj_asm_x86.h
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@@ -1956,7 +1956,7 @@ static void asm_bswap(ASMState *as, IRIns *ir)
#define asm_bor(as, ir) asm_intarith(as, ir, XOg_OR)
#define asm_bxor(as, ir) asm_intarith(as, ir, XOg_XOR)
static void asm_bitshift(ASMState *as, IRIns *ir, x86Shift xs)
static void asm_bitshift(ASMState *as, IRIns *ir, x86Shift xs, x86Op xv)
{
IRRef rref = ir->op2;
IRIns *irr = IR(rref);
@@ -1965,11 +1965,27 @@ static void asm_bitshift(ASMState *as, IRIns *ir, x86Shift xs)
int shift;
dest = ra_dest(as, ir, RSET_GPR);
shift = irr->i & (irt_is64(ir->t) ? 63 : 31);
if (!xv && shift && (as->flags & JIT_F_BMI2)) {
Reg left = asm_fuseloadm(as, ir->op1, RSET_GPR, irt_is64(ir->t));
if (left != dest) { /* BMI2 rotate right by constant. */
emit_i8(as, xs == XOg_ROL ? -shift : shift);
emit_mrm(as, VEX_64IR(ir, XV_RORX), dest, left);
return;
}
}
switch (shift) {
case 0: break;
case 1: emit_rr(as, XO_SHIFT1, REX_64IR(ir, xs), dest); break;
default: emit_shifti(as, REX_64IR(ir, xs), dest, shift); break;
}
} else if ((as->flags & JIT_F_BMI2) && xv) { /* BMI2 variable shifts. */
Reg left, right;
dest = ra_dest(as, ir, RSET_GPR);
right = ra_alloc1(as, rref, RSET_GPR);
left = asm_fuseloadm(as, ir->op1, rset_exclude(RSET_GPR, right),
irt_is64(ir->t));
emit_mrm(as, VEX_64IR(ir, xv) ^ (right << 19), dest, left);
return;
} else { /* Variable shifts implicitly use register cl (i.e. ecx). */
Reg right;
dest = ra_dest(as, ir, rset_exclude(RSET_GPR, RID_ECX));
@@ -1995,11 +2011,11 @@ static void asm_bitshift(ASMState *as, IRIns *ir, x86Shift xs)
*/
}
#define asm_bshl(as, ir) asm_bitshift(as, ir, XOg_SHL)
#define asm_bshr(as, ir) asm_bitshift(as, ir, XOg_SHR)
#define asm_bsar(as, ir) asm_bitshift(as, ir, XOg_SAR)
#define asm_brol(as, ir) asm_bitshift(as, ir, XOg_ROL)
#define asm_bror(as, ir) asm_bitshift(as, ir, XOg_ROR)
#define asm_bshl(as, ir) asm_bitshift(as, ir, XOg_SHL, XV_SHLX)
#define asm_bshr(as, ir) asm_bitshift(as, ir, XOg_SHR, XV_SHRX)
#define asm_bsar(as, ir) asm_bitshift(as, ir, XOg_SAR, XV_SARX)
#define asm_brol(as, ir) asm_bitshift(as, ir, XOg_ROL, 0)
#define asm_bror(as, ir) asm_bitshift(as, ir, XOg_ROR, 0)
/* -- Comparisons --------------------------------------------------------- */