rjmccall created this revision.
rjmccall added a reviewer: scanon.
Herald added subscribers: cfe-commits, Anastasia.
Herald added a project: clang.
Fix the predefined exponent limit macros for the 16-bit IEEE format.
The magnitude range of normalized _Float16 is 2^-14 (~6e-5) to (2-2^-10)*2^15
(65504). You might think, then, that the code is correct to defne
FLT16_MIN_EXP and FLT16_MAX_EXP to be -14 and 15 respectively. However, for
some reason the C specification actually specifies a bias for these macros:
C11 5.2.4.2.2:
- minimum negative integer such that FLT_RADIX raised to one less than
that power is a normalized floating-point number, e_min:
FLT_MIN_EXP
DBL_MIN_EXP
LDBL_MIN_EXP
- maximum integer such that FLT_RADIX raised to one less than that
power is a representable finite floating-point number, e_max:
FLT_MAX_EXP
DBL_MAX_EXP
LDBL_MAX_EXP
FLT16_MIN_EXP and FLT16_MAX_EXP should clearly be biased the same way, and
other compilers do in fact do so, as do our OpenCL headers for `half`.
Additionally, FLT16_MIN_10_EXP is just wrong.
Repository:
rC Clang
https://reviews.llvm.org/D62708
Files:
clang/lib/Frontend/InitPreprocessor.cpp
clang/test/Headers/float16.c
clang/test/Preprocessor/init.c
Index: clang/test/Preprocessor/init.c
===================================================================
--- clang/test/Preprocessor/init.c
+++ clang/test/Preprocessor/init.c
@@ -310,10 +310,10 @@
// AARCH64:#define __FLT16_HAS_QUIET_NAN__ 1
// AARCH64:#define __FLT16_MANT_DIG__ 11
// AARCH64:#define __FLT16_MAX_10_EXP__ 4
-// AARCH64:#define __FLT16_MAX_EXP__ 15
+// AARCH64:#define __FLT16_MAX_EXP__ 16
// AARCH64:#define __FLT16_MAX__ 6.5504e+4F16
-// AARCH64:#define __FLT16_MIN_10_EXP__ (-13)
-// AARCH64:#define __FLT16_MIN_EXP__ (-14)
+// AARCH64:#define __FLT16_MIN_10_EXP__ (-4)
+// AARCH64:#define __FLT16_MIN_EXP__ (-13)
// AARCH64:#define __FLT16_MIN__ 6.103515625e-5F16
// AARCH64:#define __FLT_DENORM_MIN__ 1.40129846e-45F
// AARCH64:#define __FLT_DIG__ 6
Index: clang/test/Headers/float16.c
===================================================================
--- clang/test/Headers/float16.c
+++ clang/test/Headers/float16.c
@@ -13,7 +13,7 @@
#ifndef FLT16_MIN_10_EXP
#error "Macro FLT16_MIN_10_EXP is missing."
-#elif FLT16_MIN_10_EXP > -13
+#elif FLT16_MIN_10_EXP > -4
#error "Macro FLT16_MIN_10_EXP is invalid."
#endif
@@ -21,7 +21,7 @@
#ifndef FLT16_MIN_EXP
#error "Macro FLT16_MIN_EXP is missing."
-#elif FLT16_MIN_EXP > -14
+#elif FLT16_MIN_EXP > -13
#error "Macro FLT16_MIN_EXP is invalid."
#endif
@@ -37,7 +37,7 @@
#ifndef FLT16_MAX_EXP
#error "Macro FLT16_MAX_EXP is missing."
-#elif FLT16_MAX_EXP < 15
+#elif FLT16_MAX_EXP < 16
#error "Macro FLT16_MAX_EXP is invalid."
#endif
Index: clang/lib/Frontend/InitPreprocessor.cpp
===================================================================
--- clang/lib/Frontend/InitPreprocessor.cpp
+++ clang/lib/Frontend/InitPreprocessor.cpp
@@ -122,10 +122,10 @@
"4.94065645841246544176568792868221e-324",
"1.92592994438723585305597794258492732e-34");
int MantissaDigits = PickFP(Sem, 11, 24, 53, 64, 106, 113);
- int Min10Exp = PickFP(Sem, -13, -37, -307, -4931, -291, -4931);
+ int Min10Exp = PickFP(Sem, -4, -37, -307, -4931, -291, -4931);
int Max10Exp = PickFP(Sem, 4, 38, 308, 4932, 308, 4932);
- int MinExp = PickFP(Sem, -14, -125, -1021, -16381, -968, -16381);
- int MaxExp = PickFP(Sem, 15, 128, 1024, 16384, 1024, 16384);
+ int MinExp = PickFP(Sem, -13, -125, -1021, -16381, -968, -16381);
+ int MaxExp = PickFP(Sem, 16, 128, 1024, 16384, 1024, 16384);
Min = PickFP(Sem, "6.103515625e-5", "1.17549435e-38",
"2.2250738585072014e-308",
"3.36210314311209350626e-4932",
"2.00416836000897277799610805135016e-292",
Index: clang/test/Preprocessor/init.c
===================================================================
--- clang/test/Preprocessor/init.c
+++ clang/test/Preprocessor/init.c
@@ -310,10 +310,10 @@
// AARCH64:#define __FLT16_HAS_QUIET_NAN__ 1
// AARCH64:#define __FLT16_MANT_DIG__ 11
// AARCH64:#define __FLT16_MAX_10_EXP__ 4
-// AARCH64:#define __FLT16_MAX_EXP__ 15
+// AARCH64:#define __FLT16_MAX_EXP__ 16
// AARCH64:#define __FLT16_MAX__ 6.5504e+4F16
-// AARCH64:#define __FLT16_MIN_10_EXP__ (-13)
-// AARCH64:#define __FLT16_MIN_EXP__ (-14)
+// AARCH64:#define __FLT16_MIN_10_EXP__ (-4)
+// AARCH64:#define __FLT16_MIN_EXP__ (-13)
// AARCH64:#define __FLT16_MIN__ 6.103515625e-5F16
// AARCH64:#define __FLT_DENORM_MIN__ 1.40129846e-45F
// AARCH64:#define __FLT_DIG__ 6
Index: clang/test/Headers/float16.c
===================================================================
--- clang/test/Headers/float16.c
+++ clang/test/Headers/float16.c
@@ -13,7 +13,7 @@
#ifndef FLT16_MIN_10_EXP
#error "Macro FLT16_MIN_10_EXP is missing."
-#elif FLT16_MIN_10_EXP > -13
+#elif FLT16_MIN_10_EXP > -4
#error "Macro FLT16_MIN_10_EXP is invalid."
#endif
@@ -21,7 +21,7 @@
#ifndef FLT16_MIN_EXP
#error "Macro FLT16_MIN_EXP is missing."
-#elif FLT16_MIN_EXP > -14
+#elif FLT16_MIN_EXP > -13
#error "Macro FLT16_MIN_EXP is invalid."
#endif
@@ -37,7 +37,7 @@
#ifndef FLT16_MAX_EXP
#error "Macro FLT16_MAX_EXP is missing."
-#elif FLT16_MAX_EXP < 15
+#elif FLT16_MAX_EXP < 16
#error "Macro FLT16_MAX_EXP is invalid."
#endif
Index: clang/lib/Frontend/InitPreprocessor.cpp
===================================================================
--- clang/lib/Frontend/InitPreprocessor.cpp
+++ clang/lib/Frontend/InitPreprocessor.cpp
@@ -122,10 +122,10 @@
"4.94065645841246544176568792868221e-324",
"1.92592994438723585305597794258492732e-34");
int MantissaDigits = PickFP(Sem, 11, 24, 53, 64, 106, 113);
- int Min10Exp = PickFP(Sem, -13, -37, -307, -4931, -291, -4931);
+ int Min10Exp = PickFP(Sem, -4, -37, -307, -4931, -291, -4931);
int Max10Exp = PickFP(Sem, 4, 38, 308, 4932, 308, 4932);
- int MinExp = PickFP(Sem, -14, -125, -1021, -16381, -968, -16381);
- int MaxExp = PickFP(Sem, 15, 128, 1024, 16384, 1024, 16384);
+ int MinExp = PickFP(Sem, -13, -125, -1021, -16381, -968, -16381);
+ int MaxExp = PickFP(Sem, 16, 128, 1024, 16384, 1024, 16384);
Min = PickFP(Sem, "6.103515625e-5", "1.17549435e-38", "2.2250738585072014e-308",
"3.36210314311209350626e-4932",
"2.00416836000897277799610805135016e-292",
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