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Remove Mono LLVM MinNumber workaround #132488

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Remove Mono LLVM MinNumber workaround #132488

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4 changes: 2 additions & 2 deletions src/mono/mono/mini/intrinsics.c
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Original file line number Diff line number Diff line change
Expand Up @@ -297,8 +297,8 @@ llvm_emit_inst_for_method (MonoCompile *cfg, MonoMethod *cmethod, MonoMethodSign
//
// * MinNumber / MaxNumber: IEEE 754-2019 minimumNumber / maximumNumber
// (NaN-suppressing and sign-of-zero aware, treating -0 as less than +0).
// Lowered in mini-llvm.c by composing llvm.minimum / llvm.maximum with an
// explicit NaN fixup; see the OP_FMINNUM case there and llvm-intrinsics.h.
// Lower to llvm.minimumnum / llvm.maximumnum, which on AArch64 maps to a
// single fminnm / fmaxnm instruction; see mini-llvm.c and llvm-intrinsics.h.
// * 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.
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11 changes: 7 additions & 4 deletions src/mono/mono/mini/llvm-intrinsics.h
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Expand Up @@ -98,11 +98,14 @@ INTRINS_OVR(TRUNCF, trunc, Generic, LLVMFloatType ())
INTRINS_OVR(COPYSIGN, copysign, Generic, LLVMDoubleType ())
INTRINS_OVR(COPYSIGNF, copysign, Generic, LLVMFloatType ())
/*
* `float.MinNumber` / `double.MinNumber` (and the Max variants) are lowered in
* mini-llvm.c by composing llvm.minimum/maximum (above) with an explicit NaN
* fixup; see the OP_FMINNUM case there for why we don't use llvm.minnum/maxnum
* or llvm.minimumnum/maximumnum directly.
* IEEE 754-2019 minimumNumber/maximumNumber (NaN-suppressing and sign-of-zero
* aware). Use llvm.minimum/maximum (above) for the NaN-propagating
* Math.Min/Math.Max instead.
*/
INTRINS_OVR(MINIMUMNUM, minimumnum, Generic, LLVMDoubleType ())
INTRINS_OVR(MINIMUMNUMF, minimumnum, Generic, LLVMFloatType ())
INTRINS_OVR(MAXIMUMNUM, maximumnum, Generic, LLVMDoubleType ())
INTRINS_OVR(MAXIMUMNUMF, maximumnum, Generic, LLVMFloatType ())
INTRINS_OVR(EXPECT_I8, expect, Generic, LLVMInt8Type ())
INTRINS_OVR(EXPECT_I1, expect, Generic, LLVMInt1Type ())
INTRINS_OVR(CTPOP_I32, ctpop, Generic, LLVMInt32Type ())
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34 changes: 11 additions & 23 deletions src/mono/mono/mini/mini-llvm.c
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Expand Up @@ -7628,32 +7628,20 @@ MONO_RESTORE_WARNING
case OP_RMAXNUM: {
/*
* IEEE 754-2019 minimumNumber/maximumNumber (NaN-suppressing and
* sign-of-zero aware), as specified by `float.MinNumber` /
* `double.MinNumber` (and the Max variants, surfaced via
* INumber<TSelf> on the primitive Single/Double/Half types).
*
* We compose this from llvm.minimum/maximum (sign-of-zero aware but
* NaN-propagating) plus an explicit NaN fixup, rather than lowering
* directly to an intrinsic: llvm.minnum/maxnum leave the sign of zero
* unspecified (minnum(+0, -0) may return +0 on x86, see dotnet/runtime
* #131130) and llvm.minimumnum/maximumnum are miscompiled by the x86
* backend in the LLVM version we build against. When exactly one operand
* is NaN we return the other; when both are NaN the NaN flows through.
* sign-of-zero aware). Maps directly to llvm.minimumnum/maximumnum.
*/
gboolean is_r4 = ins->opcode == OP_RMINNUM || ins->opcode == OP_RMAXNUM;
gboolean is_max = ins->opcode == OP_FMAXNUM || ins->opcode == OP_RMAXNUM;
LLVMTypeRef t = is_r4 ? LLVMFloatType () : LLVMDoubleType ();
LLVMValueRef l = convert (ctx, lhs, t);
LLVMValueRef r = convert (ctx, rhs, t);
LLVMValueRef args [2] = { l, r };
IntrinsicId iid = is_max ? (is_r4 ? INTRINS_MAXIMUMF : INTRINS_MAXIMUM)
: (is_r4 ? INTRINS_MINIMUMF : INTRINS_MINIMUM);
LLVMValueRef result = call_intrins (ctx, iid, args, "");
LLVMValueRef l_nan = LLVMBuildFCmp (builder, LLVMRealUNO, l, l, "");
LLVMValueRef r_nan = LLVMBuildFCmp (builder, LLVMRealUNO, r, r, "");
result = LLVMBuildSelect (builder, r_nan, l, result, "");
result = LLVMBuildSelect (builder, l_nan, r, result, dname);
values [ins->dreg] = result;
LLVMValueRef args [2] = { convert (ctx, lhs, t), convert (ctx, rhs, t) };
IntrinsicId iid;
switch (ins->opcode) {
case OP_FMAXNUM: iid = INTRINS_MAXIMUMNUM; break;
case OP_FMINNUM: iid = INTRINS_MINIMUMNUM; break;
case OP_RMAXNUM: iid = INTRINS_MAXIMUMNUMF; break;
case OP_RMINNUM: iid = INTRINS_MINIMUMNUMF; break;
default: g_assert_not_reached (); break;
}
values [ins->dreg] = call_intrins (ctx, iid, args, dname);
break;
}

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