[libc-commits] [libc] b629414 - [libc][NFC] Simplify logic in `sqrt` (#80426)

[via libc-commits]

Author: Guillaume Chatelet
Date: 2024-02-02T17:21:30+01:00
New Revision: b629414ae13d6dcd641e92d0389c5d4b7638a644

URL: https://github.com/llvm/llvm-project/commit/b629414ae13d6dcd641e92d0389c5d4b7638a644
DIFF: https://github.com/llvm/llvm-project/commit/b629414ae13d6dcd641e92d0389c5d4b7638a644.diff

LOG: [libc][NFC] Simplify logic in `sqrt` (#80426)

Added: 
    

Modified: 
    libc/src/__support/FPUtil/generic/sqrt.h
    libc/src/__support/FPUtil/generic/sqrt_80_bit_long_double.h

Removed: 
    


################################################################################
diff  --git a/libc/src/__support/FPUtil/generic/sqrt.h b/libc/src/__support/FPUtil/generic/sqrt.h
index 702de3f04a9bf..9e8ed305eeca5 100644
--- a/libc/src/__support/FPUtil/generic/sqrt.h
+++ b/libc/src/__support/FPUtil/generic/sqrt.h
@@ -78,21 +78,16 @@ LIBC_INLINE cpp::enable_if_t<cpp::is_floating_point_v<T>, T> sqrt(T x) {
 
     FPBits_t bits(x);
 
-    if (bits.is_inf_or_nan()) {
-      if (bits.is_neg() && (bits.get_mantissa() == 0)) {
-        // sqrt(-Inf) = NaN
-        return FLT_NAN;
-      } else {
-        // sqrt(NaN) = NaN
-        // sqrt(+Inf) = +Inf
-        return x;
-      }
-    } else if (bits.is_zero()) {
+    if (bits == FPBits_t::inf(Sign::POS) || bits.is_zero() || bits.is_nan()) {
+      // sqrt(+Inf) = +Inf
       // sqrt(+0) = +0
       // sqrt(-0) = -0
+      // sqrt(NaN) = NaN
+      // sqrt(-NaN) = -NaN
       return x;
     } else if (bits.is_neg()) {
-      // sqrt( negative numbers ) = NaN
+      // sqrt(-Inf) = NaN
+      // sqrt(-x) = NaN
       return FLT_NAN;
     } else {
       int x_exp = bits.get_exponent();

diff  --git a/libc/src/__support/FPUtil/generic/sqrt_80_bit_long_double.h b/libc/src/__support/FPUtil/generic/sqrt_80_bit_long_double.h
index 74a536c04817c..4b2af10256176 100644
--- a/libc/src/__support/FPUtil/generic/sqrt_80_bit_long_double.h
+++ b/libc/src/__support/FPUtil/generic/sqrt_80_bit_long_double.h
@@ -43,21 +43,16 @@ LIBC_INLINE long double sqrt(long double x) {
 
   LDBits bits(x);
 
-  if (bits.is_inf_or_nan()) {
-    if (bits.is_neg() && (bits.get_mantissa() == 0)) {
-      // sqrt(-Inf) = NaN
-      return LDNAN;
-    } else {
-      // sqrt(NaN) = NaN
-      // sqrt(+Inf) = +Inf
-      return x;
-    }
-  } else if (bits.is_zero()) {
+  if (bits == LDBits::inf(Sign::POS) || bits.is_zero() || bits.is_nan()) {
+    // sqrt(+Inf) = +Inf
     // sqrt(+0) = +0
     // sqrt(-0) = -0
+    // sqrt(NaN) = NaN
+    // sqrt(-NaN) = -NaN
     return x;
   } else if (bits.is_neg()) {
-    // sqrt( negative numbers ) = NaN
+    // sqrt(-Inf) = NaN
+    // sqrt(-x) = NaN
     return LDNAN;
   } else {
     int x_exp = bits.get_explicit_exponent();