[llvm-branch-commits] [compiler-rt] release/18.x: Unbreak *tf builtins for hexfloat (#82208) (PR #82904)
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Sat Feb 24 20:16:19 PST 2024
https://github.com/llvmbot created https://github.com/llvm/llvm-project/pull/82904
Backport 99c457dc2ef395872d7448c85609f6cb73a7f89b
Requested by: @brad0
>From 4de7aeb2176f6a05e427d57149596c376d5b148d Mon Sep 17 00:00:00 2001
From: Alexander Richardson <alexrichardson at google.com>
Date: Wed, 21 Feb 2024 12:59:56 -0800
Subject: [PATCH] Unbreak *tf builtins for hexfloat (#82208)
This re-lands cc0065a7d082f0bd322a538cf62cfaef1c8f89f8 in a way that
keeps existing targets working.
---------
Original commit message:
#68132 ended up removing
__multc3 & __divtc3 from compiler-rt library builds that have
QUAD_PRECISION but not TF_MODE due to missing int128 support.
I added support for QUAD_PRECISION to use the native hex float long double representation.
---------
Co-authored-by: Sean Perry <perry at ca.ibm.com>
(cherry picked from commit 99c457dc2ef395872d7448c85609f6cb73a7f89b)
---
compiler-rt/lib/builtins/divtc3.c | 2 +-
compiler-rt/lib/builtins/fp_lib.h | 41 ++++++++++++++++++----------
compiler-rt/lib/builtins/int_types.h | 8 ++++--
compiler-rt/lib/builtins/multc3.c | 2 +-
4 files changed, 34 insertions(+), 19 deletions(-)
diff --git a/compiler-rt/lib/builtins/divtc3.c b/compiler-rt/lib/builtins/divtc3.c
index e970cef574b21d..099de5802daf0e 100644
--- a/compiler-rt/lib/builtins/divtc3.c
+++ b/compiler-rt/lib/builtins/divtc3.c
@@ -13,7 +13,7 @@
#define QUAD_PRECISION
#include "fp_lib.h"
-#if defined(CRT_HAS_TF_MODE)
+#if defined(CRT_HAS_F128)
// Returns: the quotient of (a + ib) / (c + id)
diff --git a/compiler-rt/lib/builtins/fp_lib.h b/compiler-rt/lib/builtins/fp_lib.h
index af406e760497a4..c4f0a5b9587f77 100644
--- a/compiler-rt/lib/builtins/fp_lib.h
+++ b/compiler-rt/lib/builtins/fp_lib.h
@@ -22,6 +22,7 @@
#include "int_lib.h"
#include "int_math.h"
+#include "int_types.h"
#include <limits.h>
#include <stdbool.h>
#include <stdint.h>
@@ -93,13 +94,14 @@ static __inline void wideMultiply(rep_t a, rep_t b, rep_t *hi, rep_t *lo) {
COMPILER_RT_ABI fp_t __adddf3(fp_t a, fp_t b);
#elif defined QUAD_PRECISION
-#if defined(CRT_HAS_TF_MODE)
+#if defined(CRT_HAS_F128) && defined(CRT_HAS_128BIT)
typedef uint64_t half_rep_t;
typedef __uint128_t rep_t;
typedef __int128_t srep_t;
typedef tf_float fp_t;
#define HALF_REP_C UINT64_C
#define REP_C (__uint128_t)
+#if defined(CRT_HAS_IEEE_TF)
// Note: Since there is no explicit way to tell compiler the constant is a
// 128-bit integer, we let the constant be casted to 128-bit integer
#define significandBits 112
@@ -188,7 +190,10 @@ static __inline void wideMultiply(rep_t a, rep_t b, rep_t *hi, rep_t *lo) {
#undef Word_HiMask
#undef Word_LoMask
#undef Word_FullMask
-#endif // defined(CRT_HAS_TF_MODE)
+#endif // defined(CRT_HAS_IEEE_TF)
+#else
+typedef long double fp_t;
+#endif // defined(CRT_HAS_F128) && defined(CRT_HAS_128BIT)
#else
#error SINGLE_PRECISION, DOUBLE_PRECISION or QUAD_PRECISION must be defined.
#endif
@@ -196,19 +201,6 @@ static __inline void wideMultiply(rep_t a, rep_t b, rep_t *hi, rep_t *lo) {
#if defined(SINGLE_PRECISION) || defined(DOUBLE_PRECISION) || \
(defined(QUAD_PRECISION) && defined(CRT_HAS_TF_MODE))
#define typeWidth (sizeof(rep_t) * CHAR_BIT)
-#define exponentBits (typeWidth - significandBits - 1)
-#define maxExponent ((1 << exponentBits) - 1)
-#define exponentBias (maxExponent >> 1)
-
-#define implicitBit (REP_C(1) << significandBits)
-#define significandMask (implicitBit - 1U)
-#define signBit (REP_C(1) << (significandBits + exponentBits))
-#define absMask (signBit - 1U)
-#define exponentMask (absMask ^ significandMask)
-#define oneRep ((rep_t)exponentBias << significandBits)
-#define infRep exponentMask
-#define quietBit (implicitBit >> 1)
-#define qnanRep (exponentMask | quietBit)
static __inline rep_t toRep(fp_t x) {
const union {
@@ -226,6 +218,21 @@ static __inline fp_t fromRep(rep_t x) {
return rep.f;
}
+#if !defined(QUAD_PRECISION) || defined(CRT_HAS_IEEE_TF)
+#define exponentBits (typeWidth - significandBits - 1)
+#define maxExponent ((1 << exponentBits) - 1)
+#define exponentBias (maxExponent >> 1)
+
+#define implicitBit (REP_C(1) << significandBits)
+#define significandMask (implicitBit - 1U)
+#define signBit (REP_C(1) << (significandBits + exponentBits))
+#define absMask (signBit - 1U)
+#define exponentMask (absMask ^ significandMask)
+#define oneRep ((rep_t)exponentBias << significandBits)
+#define infRep exponentMask
+#define quietBit (implicitBit >> 1)
+#define qnanRep (exponentMask | quietBit)
+
static __inline int normalize(rep_t *significand) {
const int shift = rep_clz(*significand) - rep_clz(implicitBit);
*significand <<= shift;
@@ -328,6 +335,8 @@ static __inline fp_t __compiler_rt_scalbnX(fp_t x, int y) {
return fromRep(sign | ((rep_t)exp << significandBits) | sig);
}
+#endif // !defined(QUAD_PRECISION) || defined(CRT_HAS_IEEE_TF)
+
// Avoid using fmax from libm.
static __inline fp_t __compiler_rt_fmaxX(fp_t x, fp_t y) {
// If either argument is NaN, return the other argument. If both are NaN,
@@ -405,6 +414,8 @@ static __inline tf_float __compiler_rt_fmaxtf(tf_float x, tf_float y) {
#define __compiler_rt_logbl crt_logbl
#define __compiler_rt_scalbnl crt_scalbnl
#define __compiler_rt_fmaxl crt_fmaxl
+#define crt_fabstf crt_fabsl
+#define crt_copysigntf crt_copysignl
#else
#error Unsupported TF mode type
#endif
diff --git a/compiler-rt/lib/builtins/int_types.h b/compiler-rt/lib/builtins/int_types.h
index 7624c728061518..ca97391fc28466 100644
--- a/compiler-rt/lib/builtins/int_types.h
+++ b/compiler-rt/lib/builtins/int_types.h
@@ -189,12 +189,16 @@ typedef long double tf_float;
#define CRT_LDBL_IEEE_F128
#endif
#define TF_C(x) x##L
-#elif __LDBL_MANT_DIG__ == 113
-// Use long double instead of __float128 if it matches the IEEE 128-bit format.
+#elif __LDBL_MANT_DIG__ == 113 || \
+ (__FLT_RADIX__ == 16 && __LDBL_MANT_DIG__ == 28)
+// Use long double instead of __float128 if it matches the IEEE 128-bit format
+// or the IBM hexadecimal format.
#define CRT_LDBL_128BIT
#define CRT_HAS_F128
+#if __LDBL_MANT_DIG__ == 113
#define CRT_HAS_IEEE_TF
#define CRT_LDBL_IEEE_F128
+#endif
typedef long double tf_float;
#define TF_C(x) x##L
#elif defined(__FLOAT128__) || defined(__SIZEOF_FLOAT128__)
diff --git a/compiler-rt/lib/builtins/multc3.c b/compiler-rt/lib/builtins/multc3.c
index f20e53ccbf233b..61a3f45e47279c 100644
--- a/compiler-rt/lib/builtins/multc3.c
+++ b/compiler-rt/lib/builtins/multc3.c
@@ -15,7 +15,7 @@
#include "int_lib.h"
#include "int_math.h"
-#if defined(CRT_HAS_TF_MODE)
+#if defined(CRT_HAS_F128)
// Returns: the product of a + ib and c + id
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