149f5b573c
This is an alternate fix (see D87835) for a bug where a NaN constant gets wrongly transformed into Infinity via truncation. In this patch, we uniformly convert any SNaN to QNaN while raising 'invalid op'. But we don't have a way to directly specify a 32-bit SNaN value in LLVM IR, so those are always encoded/decoded by calling convert from/to 64-bit hex. See D88664 for a clang fix needed to allow this change. Differential Revision: https://reviews.llvm.org/D88238
22 lines
792 B
C
22 lines
792 B
C
// RUN: %clang -target mipsel-unknown-linux -mnan=legacy -emit-llvm -S %s -o - | FileCheck %s
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// CHECK: float 0x7FFC000000000000, float 0x7FF8000000000000
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// CHECK: double 0x7FF4000000000000, double 0x7FF8000000000000
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// The first line shows an unintended consequence.
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// __builtin_nan() creates a legacy QNAN double with an empty payload
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// (the first bit of the significand is clear to indicate quiet, so
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// the second bit of the payload is set to maintain NAN-ness).
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// The value is then truncated, but llvm::APFloat does not know about
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// the inverted quiet bit, so it sets the first bit on conversion
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// to indicate 'quiet' independently of the setting in clang.
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float f[] = {
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__builtin_nan(""),
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__builtin_nans(""),
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};
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double d[] = {
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__builtin_nan(""),
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__builtin_nans(""),
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};
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