[libc] fix -Wconversion in float_to_string.h #74369
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Fixes:
libc/src/__support/float_to_string.h:551:48: error: conversion from ‘long
unsigned int’ to ‘int32_t’ {aka ‘int’} may change value [-Werror=conversion]
551 | const int32_t shift_amount = SHIFT_CONST + (-exponent - IDX_SIZE * idx);
| ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Observed in gcc fullbuilds.
IDX_SIZE is a size_t (aka 'long unsigned int'), but has the value 128, so the
expression is undergoing implicit promotion.
Link: https://lab.llvm.org/buildbot/#/builders/250/builds/14891
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@llvm/pr-subscribers-libc Author: Nick Desaulniers (nickdesaulniers) ChangesFixes: Observed in gcc fullbuilds. IDX_SIZE is a size_t (aka 'long unsigned int'), but has the value 128, so the Link: https://lab.llvm.org/buildbot/#/builders/250/builds/14891 Full diff: https://github.com/llvm/llvm-project/pull/74369.diff 1 Files Affected:
diff --git a/libc/src/__support/float_to_string.h b/libc/src/__support/float_to_string.h
index 1bb4e5c5b9246..f1471d0710277 100644
--- a/libc/src/__support/float_to_string.h
+++ b/libc/src/__support/float_to_string.h
@@ -548,7 +548,7 @@ class FloatToString {
val = POW10_SPLIT_2[p];
#endif
- const int32_t shift_amount = SHIFT_CONST + (-exponent - IDX_SIZE * idx);
+ const int32_t shift_amount = SHIFT_CONST + (-exponent - static_cast<int>(IDX_SIZE) * idx);
uint32_t digits =
internal::mul_shift_mod_1e9(mantissa, val, shift_amount);
return digits;
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✅ With the latest revision this PR passed the C/C++ code formatter. |
Patch llvm#74369 fixed one of the fixed in the previous commit. This rebases on top of that commit and also adjusts the casts in that file to better match.
Fixes:
libc/src/__support/float_to_string.h:551:48: error: conversion from ‘long
unsigned int’ to ‘int32_t’ {aka ‘int’} may change value [-Werror=conversion]
551 | const int32_t shift_amount = SHIFT_CONST + (-exponent - IDX_SIZE * idx);
| ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Observed in gcc fullbuilds.
IDX_SIZE is a size_t (aka 'long unsigned int'), but has the value 128, so the
expression is undergoing implicit promotion.
Link: https://lab.llvm.org/buildbot/#/builders/250/builds/14891