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[mono][llvm] Recognize MathF.Abs/Log and Single/Double.MinNumber/MaxNumber as intrinsics #129699

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Merged
lewing merged 2 commits into from
Jun 23, 2026
Merged

[mono][llvm] Recognize MathF.Abs/Log and Single/Double.MinNumber/MaxNumber as intrinsics #129699

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4c1fbd3
[mono][llvm] Recognize MathF.Abs/Log and Single/Double.MinNumber/MaxN…
lewing Jun 18, 2026
24f3b7e
Address review: recognize Single/Double.Abs and fix comment wording
lewing Jun 22, 2026
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46 changes: 45 additions & 1 deletion src/mono/mono/mini/intrinsics.c
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Original file line number Diff line number Diff line change
Expand Up @@ -102,14 +102,18 @@ llvm_emit_inst_for_method (MonoCompile *cfg, MonoMethod *cmethod, MonoMethodSign
if (in_corlib && !strcmp (m_class_get_name (cmethod->klass), "MathF") && cfg->r4fp) {
// (float)
if (fsig->param_count == 1 && fsig->params [0]->type == MONO_TYPE_R4) {
if (!strcmp (cmethod->name, "Ceiling")) {
if (!strcmp (cmethod->name, "Abs")) {
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opcode = OP_ABSF;
} else if (!strcmp (cmethod->name, "Ceiling")) {
opcode = OP_CEILF;
} else if (!strcmp (cmethod->name, "Cos")) {
opcode = OP_COSF;
} else if (!strcmp (cmethod->name, "Exp")) {
opcode = OP_EXPF;
} else if (!strcmp (cmethod->name, "Floor")) {
opcode = OP_FLOORF;
} else if (!strcmp (cmethod->name, "Log")) {
opcode = OP_LOGF;
} else if (!strcmp (cmethod->name, "Log2")) {
opcode = OP_LOG2F;
} else if (!strcmp (cmethod->name, "Log10")) {
Expand Down Expand Up @@ -285,6 +289,46 @@ llvm_emit_inst_for_method (MonoCompile *cfg, MonoMethod *cmethod, MonoMethodSign
}
}

if (in_corlib && (!strcmp (m_class_get_name (cmethod->klass), "Single") || !strcmp (m_class_get_name (cmethod->klass), "Double"))) {
// Recognize a handful of helpers on the primitive `Single` / `Double` types
// (forwarded from INumberBase<TSelf> / INumber<TSelf>). These don't have
// corresponding APIs on Math/MathF -- e.g. there is no `Math.MinNumber` --
// so the existing Math/MathF block above doesn't catch them.
//
// * MinNumber / MaxNumber: IEEE 754-2008 minNum / maxNum (NaN-suppressing).
// Lower to llvm.minnum / llvm.maxnum, which on AArch64 maps to a single
// fminnm / fmaxnm instruction; matches the BCL spec "if either is NaN
// return the non-NaN; if both are NaN return NaN".
// * Abs: BCL forwarder to MathF.Abs / Math.Abs. Today this usually inlines
// into the Math/MathF recognition above, but adding direct recognition
// keeps the lowering working even if the JIT inliner declines.
opcode = 0;
if (fsig->param_count == 1 &&
(fsig->params [0]->type == MONO_TYPE_R4 || fsig->params [0]->type == MONO_TYPE_R8)) {
gboolean is_r4 = fsig->params [0]->type == MONO_TYPE_R4;
if (!strcmp (cmethod->name, "Abs"))
opcode = is_r4 ? OP_ABSF : OP_ABS;
}
if (fsig->param_count == 2 &&
fsig->params [0]->type == fsig->params [1]->type &&
(fsig->params [0]->type == MONO_TYPE_R4 || fsig->params [0]->type == MONO_TYPE_R8)) {
gboolean is_r4 = fsig->params [0]->type == MONO_TYPE_R4;
if (!strcmp (cmethod->name, "MaxNumber"))
opcode = is_r4 ? OP_RMAXNUM : OP_FMAXNUM;
else if (!strcmp (cmethod->name, "MinNumber"))
opcode = is_r4 ? OP_RMINNUM : OP_FMINNUM;
}
if (opcode) {
MONO_INST_NEW (cfg, ins, opcode);
ins->type = STACK_R8;
ins->dreg = mono_alloc_dreg (cfg, (MonoStackType)ins->type);
ins->sreg1 = args [0]->dreg;
if (fsig->param_count > 1)
ins->sreg2 = args [1]->dreg;
MONO_ADD_INS (cfg->cbb, ins);
}
}

if (in_corlib && !strcmp (m_class_get_name (cmethod->klass), "SpanHelpers")) {
if (!strcmp (cmethod->name, "Memmove") && fsig->param_count == 3 && m_type_is_byref (fsig->params [0]) && m_type_is_byref (fsig->params [1]) && !cmethod->is_inflated) {
MonoBasicBlock *end_bb;
Expand Down
14 changes: 14 additions & 0 deletions src/mono/mono/mini/llvm-intrinsics.h
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Expand Up @@ -88,6 +88,7 @@ INTRINS_OVR(POW, pow, Generic, LLVMDoubleType ())
INTRINS_OVR(EXP, exp, Generic, LLVMDoubleType ())
INTRINS_OVR(EXPF, exp, Generic, LLVMFloatType ())
INTRINS_OVR(LOG, log, Generic, LLVMDoubleType ())
INTRINS_OVR(LOGF, log, Generic, LLVMFloatType ())
INTRINS_OVR(LOG2, log2, Generic, LLVMDoubleType ())
INTRINS_OVR(LOG2F, log2, Generic, LLVMFloatType ())
INTRINS_OVR(LOG10, log10, Generic, LLVMDoubleType ())
Expand All @@ -96,6 +97,19 @@ INTRINS_OVR(TRUNC, trunc, Generic, LLVMDoubleType ())
INTRINS_OVR(TRUNCF, trunc, Generic, LLVMFloatType ())
INTRINS_OVR(COPYSIGN, copysign, Generic, LLVMDoubleType ())
INTRINS_OVR(COPYSIGNF, copysign, Generic, LLVMFloatType ())
/*
* IEEE 754-2008 minNum/maxNum (NaN-suppressing). When exactly one operand
* is NaN they return the other; when both are NaN they return NaN. This is
* what `float.MinNumber` / `double.MinNumber` (and the Max variants,
* surfaced via INumber<TSelf> on the primitive Single/Double/Half types)
* are documented to do, and on AArch64 these lower to single fminnm/fmaxnm
* instructions. Use llvm.minimum/maximum (see above) for the NaN-propagating
* Math.Min/Math.Max instead.
*/
INTRINS_OVR(MINNUM, minnum, Generic, LLVMDoubleType ())
INTRINS_OVR(MINNUMF, minnum, Generic, LLVMFloatType ())
INTRINS_OVR(MAXNUM, maxnum, Generic, LLVMDoubleType ())
INTRINS_OVR(MAXNUMF, maxnum, Generic, LLVMFloatType ())
INTRINS_OVR(EXPECT_I8, expect, Generic, LLVMInt8Type ())
INTRINS_OVR(EXPECT_I1, expect, Generic, LLVMInt1Type ())
INTRINS_OVR(CTPOP_I32, ctpop, Generic, LLVMInt32Type ())
Expand Down
33 changes: 33 additions & 0 deletions src/mono/mono/mini/mini-llvm.c
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Expand Up @@ -7494,6 +7494,13 @@ MONO_RESTORE_WARNING
values [ins->dreg] = call_intrins (ctx, INTRINS_LOG, args, dname);
break;
}
case OP_LOGF: {
LLVMValueRef args [1];

args [0] = convert (ctx, lhs, LLVMFloatType ());
values [ins->dreg] = call_intrins (ctx, INTRINS_LOGF, args, dname);
break;
}
case OP_TRUNC: {
LLVMValueRef args [1];

Expand Down Expand Up @@ -7703,6 +7710,32 @@ MONO_RESTORE_WARNING
break;
}

case OP_FMINNUM:
case OP_FMAXNUM:
case OP_RMINNUM:
case OP_RMAXNUM: {
/*
* IEEE 754-2008 minNum/maxNum (NaN-suppressing). Maps directly to
* llvm.minnum/maxnum, which is what `float.MinNumber` /
* `double.MinNumber` (and the Max variants, surfaced via
* INumber<TSelf> on the primitive Single/Double/Half types) specify.
* On AArch64 this lowers to a single fminnm/fmaxnm instruction.
*/
gboolean is_r4 = ins->opcode == OP_RMINNUM || ins->opcode == OP_RMAXNUM;
LLVMTypeRef t = is_r4 ? LLVMFloatType () : LLVMDoubleType ();
LLVMValueRef args [2] = { convert (ctx, lhs, t), convert (ctx, rhs, t) };
IntrinsicId iid;
switch (ins->opcode) {
case OP_FMAXNUM: iid = INTRINS_MAXNUM; break;
case OP_FMINNUM: iid = INTRINS_MINNUM; break;
case OP_RMAXNUM: iid = INTRINS_MAXNUMF; break;
case OP_RMINNUM: iid = INTRINS_MINNUMF; break;
default: g_assert_not_reached (); break;
}
values [ins->dreg] = call_intrins (ctx, iid, args, dname);
break;
}

/*
* See the ARM64 comment in mono/utils/atomic.h for an explanation of why this
* hack is necessary (for now).
Expand Down
5 changes: 5 additions & 0 deletions src/mono/mono/mini/mini-ops.h
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Expand Up @@ -684,9 +684,13 @@ MINI_OP(OP_LMIN, "long_min", LREG, LREG, LREG)
MINI_OP(OP_LMAX, "long_max", LREG, LREG, LREG)
MINI_OP(OP_RMAX, "rmax", FREG, FREG, FREG)
MINI_OP(OP_RMIN, "rmin", FREG, FREG, FREG)
MINI_OP(OP_RMAXNUM, "rmaxnum", FREG, FREG, FREG)
MINI_OP(OP_RMINNUM, "rminnum", FREG, FREG, FREG)
MINI_OP(OP_RPOW, "rpow", FREG, FREG, FREG)
MINI_OP(OP_FMAX, "fmax", FREG, FREG, FREG)
MINI_OP(OP_FMIN, "fmin", FREG, FREG, FREG)
MINI_OP(OP_FMAXNUM, "fmaxnum", FREG, FREG, FREG)
MINI_OP(OP_FMINNUM, "fminnum", FREG, FREG, FREG)
MINI_OP(OP_FPOW, "fpow", FREG, FREG, FREG)
MINI_OP(OP_RCOPYSIGN,"rcopysign", FREG, FREG, FREG)
MINI_OP(OP_FCOPYSIGN,"fcopysign", FREG, FREG, FREG)
Expand Down Expand Up @@ -740,6 +744,7 @@ MINI_OP(OP_LOG2, "log2", FREG, FREG, NONE)
MINI_OP(OP_LOG2F, "log2f", FREG, FREG, NONE)
MINI_OP(OP_LOG10, "log10", FREG, FREG, NONE)
MINI_OP(OP_LOG10F, "log10f", FREG, FREG, NONE)
MINI_OP(OP_LOGF, "logf", FREG, FREG, NONE)
MINI_OP(OP_TRUNC, "trunc", FREG, FREG, NONE)
MINI_OP(OP_TRUNCF, "truncf", FREG, FREG, NONE)
MINI_OP(OP_ABSF, "absf", FREG, FREG, NONE)
Expand Down
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