[builtins] Use single line C++/C99 comment style

Use the uniform single line C++/99 style for code comments.

This is part of the cleanup proposed in "[RFC] compiler-rt builtins
cleanup and refactoring".

Differential Revision: https://reviews.llvm.org/D60352

llvm-svn: 359411

13 files changed, 165 insertions, 192 deletions

diff --git a/compiler-rt/lib/builtins/ppc/DD.h b/compiler-rt/lib/builtins/ppc/DD.h
index 542f7e7815b..8f31a962fc7 100644
--- a/compiler-rt/lib/builtins/ppc/DD.h
+++ b/compiler-rt/lib/builtins/ppc/DD.h
@@ -42,4 +42,4 @@ long double __gcc_qsub(long double, long double);
 long double __gcc_qmul(long double, long double);
 long double __gcc_qdiv(long double, long double);
 
-#endif /* COMPILERRT_DD_HEADER */
+#endif // COMPILERRT_DD_HEADER
diff --git a/compiler-rt/lib/builtins/ppc/divtc3.c b/compiler-rt/lib/builtins/ppc/divtc3.c
index bce54e187f7..afaccf5a8fd 100644
--- a/compiler-rt/lib/builtins/ppc/divtc3.c
+++ b/compiler-rt/lib/builtins/ppc/divtc3.c
@@ -1,7 +1,6 @@
-/* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
- * See https://llvm.org/LICENSE.txt for license information.
- * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
- */
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 #include "../int_math.h"
 #include "DD.h"
@@ -13,7 +12,7 @@
 
 #if !defined(CRT_INFINITY) && defined(HUGE_VAL)
 #define CRT_INFINITY HUGE_VAL
-#endif /* CRT_INFINITY */
+#endif // CRT_INFINITY
 
 #define makeFinite(x)                                                          \
   {                                                                            \
diff --git a/compiler-rt/lib/builtins/ppc/fixtfdi.c b/compiler-rt/lib/builtins/ppc/fixtfdi.c
index d33194a68f2..a97aaf09584 100644
--- a/compiler-rt/lib/builtins/ppc/fixtfdi.c
+++ b/compiler-rt/lib/builtins/ppc/fixtfdi.c
@@ -1,11 +1,9 @@
-/* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
- * See https://llvm.org/LICENSE.txt for license information.
- * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
- */
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-/* int64_t __fixunstfdi(long double x);
- * This file implements the PowerPC 128-bit double-double -> int64_t conversion
- */
+// int64_t __fixunstfdi(long double x);
+// This file implements the PowerPC 128-bit double-double -> int64_t conversion
 
 #include "../int_math.h"
 #include "DD.h"
@@ -18,37 +16,35 @@ uint64_t __fixtfdi(long double input) {
       (uint32_t)(hibits.x >> 32) & UINT32_C(0x7fffffff);
   const uint32_t absHighWordMinusOne = absHighWord - UINT32_C(0x3ff00000);
 
-  /* If (1.0 - tiny) <= input < 0x1.0p63: */
+  // If (1.0 - tiny) <= input < 0x1.0p63:
   if (UINT32_C(0x03f00000) > absHighWordMinusOne) {
-    /* Do an unsigned conversion of the absolute value, then restore the sign.
-     */
+    // Do an unsigned conversion of the absolute value, then restore the sign.
     const int unbiasedHeadExponent = absHighWordMinusOne >> 20;
 
-    int64_t result = hibits.x & INT64_C(0x000fffffffffffff); /* mantissa(hi) */
-    result |= INT64_C(0x0010000000000000); /* matissa(hi) with implicit bit */
-    result <<= 10; /* mantissa(hi) with one zero preceding bit. */
+    int64_t result = hibits.x & INT64_C(0x000fffffffffffff); // mantissa(hi)
+    result |= INT64_C(0x0010000000000000); // matissa(hi) with implicit bit
+    result <<= 10; // mantissa(hi) with one zero preceding bit.
 
     const int64_t hiNegationMask = ((int64_t)(hibits.x)) >> 63;
 
-    /* If the tail is non-zero, we need to patch in the tail bits. */
+    // If the tail is non-zero, we need to patch in the tail bits.
     if (0.0 != x.s.lo) {
       const doublebits lobits = {.d = x.s.lo};
       int64_t tailMantissa = lobits.x & INT64_C(0x000fffffffffffff);
       tailMantissa |= INT64_C(0x0010000000000000);
 
-      /* At this point we have the mantissa of |tail| */
-      /* We need to negate it if head and tail have different signs. */
+      // At this point we have the mantissa of |tail|
+      // We need to negate it if head and tail have different signs.
       const int64_t loNegationMask = ((int64_t)(lobits.x)) >> 63;
       const int64_t negationMask = loNegationMask ^ hiNegationMask;
       tailMantissa = (tailMantissa ^ negationMask) - negationMask;
 
-      /* Now we have the mantissa of tail as a signed 2s-complement integer */
+      // Now we have the mantissa of tail as a signed 2s-complement integer
 
       const int biasedTailExponent = (int)(lobits.x >> 52) & 0x7ff;
 
-      /* Shift the tail mantissa into the right position, accounting for the
-       * bias of 10 that we shifted the head mantissa by.
-       */
+      // Shift the tail mantissa into the right position, accounting for the
+      // bias of 10 that we shifted the head mantissa by.
       tailMantissa >>=
           (unbiasedHeadExponent - (biasedTailExponent - (1023 - 10)));
 
@@ -57,36 +53,34 @@ uint64_t __fixtfdi(long double input) {
 
     result >>= (62 - unbiasedHeadExponent);
 
-    /* Restore the sign of the result and return */
+    // Restore the sign of the result and return
     result = (result ^ hiNegationMask) - hiNegationMask;
     return result;
   }
 
-  /* Edge cases handled here: */
+  // Edge cases handled here:
 
-  /* |x| < 1, result is zero. */
+  // |x| < 1, result is zero.
   if (1.0 > crt_fabs(x.s.hi))
     return INT64_C(0);
 
-  /* x very close to INT64_MIN, care must be taken to see which side we are on.
-   */
+  // x very close to INT64_MIN, care must be taken to see which side we are on.
   if (x.s.hi == -0x1.0p63) {
 
     int64_t result = INT64_MIN;
 
     if (0.0 < x.s.lo) {
-      /* If the tail is positive, the correct result is something other than
-       * INT64_MIN. we'll need to figure out what it is.
-       */
+      // If the tail is positive, the correct result is something other than
+      // INT64_MIN. we'll need to figure out what it is.
 
       const doublebits lobits = {.d = x.s.lo};
       int64_t tailMantissa = lobits.x & INT64_C(0x000fffffffffffff);
       tailMantissa |= INT64_C(0x0010000000000000);
 
-      /* Now we negate the tailMantissa */
+      // Now we negate the tailMantissa
       tailMantissa = (tailMantissa ^ INT64_C(-1)) + INT64_C(1);
 
-      /* And shift it by the appropriate amount */
+      // And shift it by the appropriate amount
       const int biasedTailExponent = (int)(lobits.x >> 52) & 0x7ff;
       tailMantissa >>= 1075 - biasedTailExponent;
 
@@ -96,7 +90,7 @@ uint64_t __fixtfdi(long double input) {
     return result;
   }
 
-  /* Signed overflows, infinities, and NaNs */
+  // Signed overflows, infinities, and NaNs
   if (x.s.hi > 0.0)
     return INT64_MAX;
   else
diff --git a/compiler-rt/lib/builtins/ppc/fixunstfdi.c b/compiler-rt/lib/builtins/ppc/fixunstfdi.c
index 11b97766213..8d53f372527 100644
--- a/compiler-rt/lib/builtins/ppc/fixunstfdi.c
+++ b/compiler-rt/lib/builtins/ppc/fixunstfdi.c
@@ -1,11 +1,9 @@
-/* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
- * See https://llvm.org/LICENSE.txt for license information.
- * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
- */
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-/* uint64_t __fixunstfdi(long double x); */
-/* This file implements the PowerPC 128-bit double-double -> uint64_t conversion
- */
+// uint64_t __fixunstfdi(long double x);
+// This file implements the PowerPC 128-bit double-double -> uint64_t conversion
 
 #include "DD.h"
 
@@ -16,33 +14,31 @@ uint64_t __fixunstfdi(long double input) {
   const uint32_t highWordMinusOne =
       (uint32_t)(hibits.x >> 32) - UINT32_C(0x3ff00000);
 
-  /* If (1.0 - tiny) <= input < 0x1.0p64: */
+  // If (1.0 - tiny) <= input < 0x1.0p64:
   if (UINT32_C(0x04000000) > highWordMinusOne) {
     const int unbiasedHeadExponent = highWordMinusOne >> 20;
 
-    uint64_t result =
-        hibits.x & UINT64_C(0x000fffffffffffff); /* mantissa(hi) */
-    result |= UINT64_C(0x0010000000000000); /* matissa(hi) with implicit bit */
-    result <<= 11; /* mantissa(hi) left aligned in the int64 field. */
+    uint64_t result = hibits.x & UINT64_C(0x000fffffffffffff); // mantissa(hi)
+    result |= UINT64_C(0x0010000000000000); // matissa(hi) with implicit bit
+    result <<= 11; // mantissa(hi) left aligned in the int64 field.
 
-    /* If the tail is non-zero, we need to patch in the tail bits. */
+    // If the tail is non-zero, we need to patch in the tail bits.
     if (0.0 != x.s.lo) {
       const doublebits lobits = {.d = x.s.lo};
       int64_t tailMantissa = lobits.x & INT64_C(0x000fffffffffffff);
       tailMantissa |= INT64_C(0x0010000000000000);
 
-      /* At this point we have the mantissa of |tail| */
+      // At this point we have the mantissa of |tail|
 
       const int64_t negationMask = ((int64_t)(lobits.x)) >> 63;
       tailMantissa = (tailMantissa ^ negationMask) - negationMask;
 
-      /* Now we have the mantissa of tail as a signed 2s-complement integer */
+      // Now we have the mantissa of tail as a signed 2s-complement integer
 
       const int biasedTailExponent = (int)(lobits.x >> 52) & 0x7ff;
 
-      /* Shift the tail mantissa into the right position, accounting for the
-       * bias of 11 that we shifted the head mantissa by.
-       */
+      // Shift the tail mantissa into the right position, accounting for the
+      // bias of 11 that we shifted the head mantissa by.
       tailMantissa >>=
           (unbiasedHeadExponent - (biasedTailExponent - (1023 - 11)));
 
@@ -53,7 +49,7 @@ uint64_t __fixunstfdi(long double input) {
     return result;
   }
 
-  /* Edge cases are handled here, with saturation. */
+  // Edge cases are handled here, with saturation.
   if (1.0 > x.s.hi)
     return UINT64_C(0);
   else
diff --git a/compiler-rt/lib/builtins/ppc/fixunstfti.c b/compiler-rt/lib/builtins/ppc/fixunstfti.c
index a6199232712..1d19e01e3a9 100644
--- a/compiler-rt/lib/builtins/ppc/fixunstfti.c
+++ b/compiler-rt/lib/builtins/ppc/fixunstfti.c
@@ -14,10 +14,10 @@
 #include "../int_math.h"
 #define BIAS 1023
 
-/* Convert long double into an unsigned 128-bit integer. */
+// Convert long double into an unsigned 128-bit integer.
 __uint128_t __fixunstfti(long double input) {
 
-  /* If we are trying to convert a NaN, return the NaN bit pattern. */
+  // If we are trying to convert a NaN, return the NaN bit pattern.
   if (crt_isnan(input)) {
     return ((__uint128_t)0x7FF8000000000000ll) << 64 |
            (__uint128_t)0x0000000000000000ll;
@@ -25,59 +25,59 @@ __uint128_t __fixunstfti(long double input) {
 
   __uint128_t result, hiResult, loResult;
   int hiExponent, loExponent, shift;
-  /* The long double representation, with the high and low portions of
-   * the long double, and the corresponding bit patterns of each double. */
+  // The long double representation, with the high and low portions of
+  // the long double, and the corresponding bit patterns of each double.
   union {
     long double ld;
-    double d[2]; /* [0] is the high double, [1] is the low double. */
-    unsigned long long ull[2]; /* High and low doubles as 64-bit integers. */
+    double d[2];               // [0] is the high double, [1] is the low double.
+    unsigned long long ull[2]; // High and low doubles as 64-bit integers.
   } ldUnion;
 
-  /* If the long double is less than 1.0 or negative,
-   * return 0.0. */
+  // If the long double is less than 1.0 or negative,
+  // return 0.0.
   if (input < 1.0)
     return 0.0;
 
-  /* Retrieve the 64-bit patterns of high and low doubles.
-   * Compute the unbiased exponent of both high and low doubles by
-   * removing the signs, isolating the exponent, and subtracting
-   * the bias from it. */
+  // Retrieve the 64-bit patterns of high and low doubles.
+  // Compute the unbiased exponent of both high and low doubles by
+  // removing the signs, isolating the exponent, and subtracting
+  // the bias from it.
   ldUnion.ld = input;
   hiExponent = ((ldUnion.ull[0] & 0x7FFFFFFFFFFFFFFFll) >> 52) - BIAS;
   loExponent = ((ldUnion.ull[1] & 0x7FFFFFFFFFFFFFFFll) >> 52) - BIAS;
 
-  /* Convert each double into int64; they will be added to the int128 result.
-   * CASE 1: High or low double fits in int64
-   *      - Convert the each double normally into int64.
-   *
-   * CASE 2: High or low double does not fit in int64
-   *      - Scale the double to fit within a 64-bit integer
-   *      - Calculate the shift (amount to scale the double by in the int128)
-   *      - Clear all the bits of the exponent (with 0x800FFFFFFFFFFFFF)
-   *      - Add BIAS+53 (0x4350000000000000) to exponent to correct the value
-   *      - Scale (move) the double to the correct place in the int128
-   *        (Move it by 2^53 places)
-   *
-   * Note: If the high double is assumed to be positive, an unsigned conversion
-   * from long double to 64-bit integer is needed. The low double can be either
-   * positive or negative, so a signed conversion is needed to retain the result
-   * of the low double and to ensure it does not simply get converted to 0. */
+  // Convert each double into int64; they will be added to the int128 result.
+  // CASE 1: High or low double fits in int64
+  //      - Convert the each double normally into int64.
+  //
+  // CASE 2: High or low double does not fit in int64
+  //      - Scale the double to fit within a 64-bit integer
+  //      - Calculate the shift (amount to scale the double by in the int128)
+  //      - Clear all the bits of the exponent (with 0x800FFFFFFFFFFFFF)
+  //      - Add BIAS+53 (0x4350000000000000) to exponent to correct the value
+  //      - Scale (move) the double to the correct place in the int128
+  //        (Move it by 2^53 places)
+  //
+  // Note: If the high double is assumed to be positive, an unsigned conversion
+  // from long double to 64-bit integer is needed. The low double can be either
+  // positive or negative, so a signed conversion is needed to retain the result
+  // of the low double and to ensure it does not simply get converted to 0.
 
-  /* CASE 1 - High double fits in int64. */
+  // CASE 1 - High double fits in int64.
   if (hiExponent < 63) {
     hiResult = (unsigned long long)ldUnion.d[0];
   } else if (hiExponent < 128) {
-    /* CASE 2 - High double does not fit in int64, scale and convert it. */
+    // CASE 2 - High double does not fit in int64, scale and convert it.
     shift = hiExponent - 54;
     ldUnion.ull[0] &= 0x800FFFFFFFFFFFFFll;
     ldUnion.ull[0] |= 0x4350000000000000ll;
     hiResult = (unsigned long long)ldUnion.d[0];
     hiResult <<= shift;
   } else {
-    /* Detect cases for overflow. When the exponent of the high
-     * double is greater than 128 bits and when the long double
-     * input is positive, return the max 128-bit integer.
-     * For negative inputs with exponents > 128, return 1, like gcc. */
+    // Detect cases for overflow. When the exponent of the high
+    // double is greater than 128 bits and when the long double
+    // input is positive, return the max 128-bit integer.
+    // For negative inputs with exponents > 128, return 1, like gcc.
     if (ldUnion.d[0] > 0) {
       return ((__uint128_t)0xFFFFFFFFFFFFFFFFll) << 64 |
              (__uint128_t)0xFFFFFFFFFFFFFFFFll;
@@ -87,11 +87,11 @@ __uint128_t __fixunstfti(long double input) {
     }
   }
 
-  /* CASE 1 - Low double fits in int64. */
+  // CASE 1 - Low double fits in int64.
   if (loExponent < 63) {
     loResult = (long long)ldUnion.d[1];
   } else {
-    /* CASE 2 - Low double does not fit in int64, scale and convert it. */
+    // CASE 2 - Low double does not fit in int64, scale and convert it.
     shift = loExponent - 54;
     ldUnion.ull[1] &= 0x800FFFFFFFFFFFFFll;
     ldUnion.ull[1] |= 0x4350000000000000ll;
@@ -99,7 +99,7 @@ __uint128_t __fixunstfti(long double input) {
     loResult <<= shift;
   }
 
-  /* Add the high and low doublewords together to form a 128 bit integer. */
+  // Add the high and low doublewords together to form a 128 bit integer.
   result = loResult + hiResult;
   return result;
 }
diff --git a/compiler-rt/lib/builtins/ppc/floatditf.c b/compiler-rt/lib/builtins/ppc/floatditf.c
index a5a4df4e097..4c365418f08 100644
--- a/compiler-rt/lib/builtins/ppc/floatditf.c
+++ b/compiler-rt/lib/builtins/ppc/floatditf.c
@@ -1,10 +1,9 @@
-/* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
- * See https://llvm.org/LICENSE.txt for license information.
- * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
- */
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-/* long double __floatditf(long long x); */
-/* This file implements the PowerPC long long -> long double conversion */
+// long double __floatditf(long long x);
+// This file implements the PowerPC long long -> long double conversion
 
 #include "DD.h"
 
@@ -14,18 +13,16 @@ long double __floatditf(int64_t a) {
   static const double twop52 = 0x1.0p52;
 
   doublebits low = {.d = twop52};
-  low.x |= a & UINT64_C(0x00000000ffffffff); /* 0x1.0p52 + low 32 bits of a. */
+  low.x |= a & UINT64_C(0x00000000ffffffff); // 0x1.0p52 + low 32 bits of a.
 
   const double high_addend = (double)((int32_t)(a >> 32)) * twop32 - twop52;
 
-  /* At this point, we have two double precision numbers
-   * high_addend and low.d, and we wish to return their sum
-   * as a canonicalized long double:
-   */
+  // At this point, we have two double precision numbers
+  // high_addend and low.d, and we wish to return their sum
+  // as a canonicalized long double:
 
-  /* This implementation sets the inexact flag spuriously.
-   * This could be avoided, but at some substantial cost.
-   */
+  // This implementation sets the inexact flag spuriously.
+  // This could be avoided, but at some substantial cost.
 
   DD result;
 
diff --git a/compiler-rt/lib/builtins/ppc/floattitf.c b/compiler-rt/lib/builtins/ppc/floattitf.c
index b722ac97828..6deac649812 100644
--- a/compiler-rt/lib/builtins/ppc/floattitf.c
+++ b/compiler-rt/lib/builtins/ppc/floattitf.c
@@ -13,35 +13,34 @@
 
 #include <stdint.h>
 
-/* Conversions from signed and unsigned 64-bit int to long double. */
+// Conversions from signed and unsigned 64-bit int to long double.
 long double __floatditf(int64_t);
 long double __floatunditf(uint64_t);
 
-/* Convert a signed 128-bit integer to long double.
- * This uses the following property:  Let hi and lo be 64-bits each,
- * and let signed_val_k() and unsigned_val_k() be the value of the
- * argument interpreted as a signed or unsigned k-bit integer. Then,
- *
- * signed_val_128(hi,lo) = signed_val_64(hi) * 2^64 + unsigned_val_64(lo)
- * = (long double)hi * 2^64 + (long double)lo,
- *
- * where (long double)hi and (long double)lo are signed and
- * unsigned 64-bit integer to long double conversions, respectively.
- */
+// Convert a signed 128-bit integer to long double.
+// This uses the following property:  Let hi and lo be 64-bits each,
+// and let signed_val_k() and unsigned_val_k() be the value of the
+// argument interpreted as a signed or unsigned k-bit integer. Then,
+//
+// signed_val_128(hi,lo) = signed_val_64(hi) * 2^64 + unsigned_val_64(lo)
+// = (long double)hi * 2^64 + (long double)lo,
+//
+// where (long double)hi and (long double)lo are signed and
+// unsigned 64-bit integer to long double conversions, respectively.
 long double __floattitf(__int128_t arg) {
-  /* Split the int128 argument into 64-bit high and low int64 parts. */
+  // Split the int128 argument into 64-bit high and low int64 parts.
   int64_t ArgHiPart = (int64_t)(arg >> 64);
   uint64_t ArgLoPart = (uint64_t)arg;
 
-  /* Convert each 64-bit part into long double. The high part
-   * must be a signed conversion and the low part an unsigned conversion
-   * to ensure the correct result. */
+  // Convert each 64-bit part into long double. The high part
+  // must be a signed conversion and the low part an unsigned conversion
+  // to ensure the correct result.
   long double ConvertedHiPart = __floatditf(ArgHiPart);
   long double ConvertedLoPart = __floatunditf(ArgLoPart);
 
-  /* The low bit of ArgHiPart corresponds to the 2^64 bit in arg.
-   * Multiply the high part by 2^64 to undo the right shift by 64-bits
-   * done in the splitting. Then, add to the low part to obtain the
-   * final result. */
+  // The low bit of ArgHiPart corresponds to the 2^64 bit in arg.
+  // Multiply the high part by 2^64 to undo the right shift by 64-bits
+  // done in the splitting. Then, add to the low part to obtain the
+  // final result.
   return ((ConvertedHiPart * 0x1.0p64) + ConvertedLoPart);
 }
diff --git a/compiler-rt/lib/builtins/ppc/floatunditf.c b/compiler-rt/lib/builtins/ppc/floatunditf.c
index d2d01d29dc3..fb4cd3f91d8 100644
--- a/compiler-rt/lib/builtins/ppc/floatunditf.c
+++ b/compiler-rt/lib/builtins/ppc/floatunditf.c
@@ -1,17 +1,15 @@
-/* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
- * See https://llvm.org/LICENSE.txt for license information.
- * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
- */
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-/* long double __floatunditf(unsigned long long x); */
-/* This file implements the PowerPC unsigned long long -> long double conversion
- */
+// long double __floatunditf(unsigned long long x);
+// This file implements the PowerPC unsigned long long -> long double conversion
 
 #include "DD.h"
 
 long double __floatunditf(uint64_t a) {
 
-  /* Begins with an exact copy of the code from __floatundidf */
+  // Begins with an exact copy of the code from __floatundidf
 
   static const double twop52 = 0x1.0p52;
   static const double twop84 = 0x1.0p84;
@@ -20,18 +18,17 @@ long double __floatunditf(uint64_t a) {
   doublebits high = {.d = twop84};
   doublebits low = {.d = twop52};
 
-  high.x |= a >> 32;                         /* 0x1.0p84 + high 32 bits of a */
-  low.x |= a & UINT64_C(0x00000000ffffffff); /* 0x1.0p52 + low 32 bits of a */
+  high.x |= a >> 32;                         // 0x1.0p84 + high 32 bits of a
+  low.x |= a & UINT64_C(0x00000000ffffffff); // 0x1.0p52 + low 32 bits of a
 
   const double high_addend = high.d - twop84_plus_twop52;
 
-  /* At this point, we have two double precision numbers
-   * high_addend and low.d, and we wish to return their sum
-   * as a canonicalized long double:
-   */
+  // At this point, we have two double precision numbers
+  // high_addend and low.d, and we wish to return their sum
+  // as a canonicalized long double:
 
-  /* This implementation sets the inexact flag spuriously. */
-  /* This could be avoided, but at some substantial cost. */
+  // This implementation sets the inexact flag spuriously.
+  // This could be avoided, but at some substantial cost.
 
   DD result;
 
diff --git a/compiler-rt/lib/builtins/ppc/gcc_qadd.c b/compiler-rt/lib/builtins/ppc/gcc_qadd.c
index e56962e4e45..6e1e63cb530 100644
--- a/compiler-rt/lib/builtins/ppc/gcc_qadd.c
+++ b/compiler-rt/lib/builtins/ppc/gcc_qadd.c
@@ -1,12 +1,10 @@
-/* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
- * See https://llvm.org/LICENSE.txt for license information.
- * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
- */
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-/* long double __gcc_qadd(long double x, long double y);
- * This file implements the PowerPC 128-bit double-double add operation.
- * This implementation is shamelessly cribbed from Apple's DDRT, circa 1993(!)
- */
+// long double __gcc_qadd(long double x, long double y);
+// This file implements the PowerPC 128-bit double-double add operation.
+// This implementation is shamelessly cribbed from Apple's DDRT, circa 1993(!)
 
 #include "DD.h"
 
@@ -17,14 +15,14 @@ long double __gcc_qadd(long double x, long double y) {
 
   register double A = dst.s.hi, a = dst.s.lo, B = src.s.hi, b = src.s.lo;
 
-  /* If both operands are zero: */
+  // If both operands are zero:
   if ((A == 0.0) && (B == 0.0)) {
     dst.s.hi = A + B;
     dst.s.lo = 0.0;
     return dst.ld;
   }
 
-  /* If either operand is NaN or infinity: */
+  // If either operand is NaN or infinity:
   const doublebits abits = {.d = A};
   const doublebits bbits = {.d = B};
   if ((((uint32_t)(abits.x >> 32) & infinityHi) == infinityHi) ||
@@ -34,9 +32,9 @@ long double __gcc_qadd(long double x, long double y) {
     return dst.ld;
   }
 
-  /* If the computation overflows: */
-  /* This may be playing things a little bit fast and loose, but it will do for
-   * a start. */
+  // If the computation overflows:
+  // This may be playing things a little bit fast and loose, but it will do for
+  // a start.
   const double testForOverflow = A + (B + (a + b));
   const doublebits testbits = {.d = testForOverflow};
   if (((uint32_t)(testbits.x >> 32) & infinityHi) == infinityHi) {
diff --git a/compiler-rt/lib/builtins/ppc/gcc_qdiv.c b/compiler-rt/lib/builtins/ppc/gcc_qdiv.c
index bbb536833e5..35a3cbc3d3f 100644
--- a/compiler-rt/lib/builtins/ppc/gcc_qdiv.c
+++ b/compiler-rt/lib/builtins/ppc/gcc_qdiv.c
@@ -1,12 +1,10 @@
-/* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
- * See https://llvm.org/LICENSE.txt for license information.
- * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
- */
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-/* long double __gcc_qdiv(long double x, long double y);
- * This file implements the PowerPC 128-bit double-double division operation.
- * This implementation is shamelessly cribbed from Apple's DDRT, circa 1993(!)
- */
+// long double __gcc_qdiv(long double x, long double y);
+// This file implements the PowerPC 128-bit double-double division operation.
+// This implementation is shamelessly cribbed from Apple's DDRT, circa 1993(!)
 
 #include "DD.h"
 
@@ -21,7 +19,7 @@ long double __gcc_qdiv(long double a, long double b) {
 
   q = x / y;
 
-  /* Detect special cases */
+  // Detect special cases
   if (q == 0.0) {
     dst.s.hi = q;
     dst.s.lo = 0.0;
diff --git a/compiler-rt/lib/builtins/ppc/gcc_qmul.c b/compiler-rt/lib/builtins/ppc/gcc_qmul.c
index efd12d8477f..75f519aad6f 100644
--- a/compiler-rt/lib/builtins/ppc/gcc_qmul.c
+++ b/compiler-rt/lib/builtins/ppc/gcc_qmul.c
@@ -1,12 +1,10 @@
-/* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
- * See https://llvm.org/LICENSE.txt for license information.
- * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
- */
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-/* long double __gcc_qmul(long double x, long double y);
- * This file implements the PowerPC 128-bit double-double multiply operation.
- * This implementation is shamelessly cribbed from Apple's DDRT, circa 1993(!)
- */
+// long double __gcc_qmul(long double x, long double y);
+// This file implements the PowerPC 128-bit double-double multiply operation.
+// This implementation is shamelessly cribbed from Apple's DDRT, circa 1993(!)
 
 #include "DD.h"
 
@@ -21,7 +19,7 @@ long double __gcc_qmul(long double x, long double y) {
 
   ab = A * B;
 
-  /* Detect special cases */
+  // Detect special cases
   if (ab == 0.0) {
     dst.s.hi = ab;
     dst.s.lo = 0.0;
@@ -35,7 +33,7 @@ long double __gcc_qmul(long double x, long double y) {
     return dst.ld;
   }
 
-  /* Generic cases handled here. */
+  // Generic cases handled here.
   aHi = high26bits(A);
   bHi = high26bits(B);
   aLo = A - aHi;
diff --git a/compiler-rt/lib/builtins/ppc/gcc_qsub.c b/compiler-rt/lib/builtins/ppc/gcc_qsub.c
index 98d20747bf5..ac08120be0b 100644
--- a/compiler-rt/lib/builtins/ppc/gcc_qsub.c
+++ b/compiler-rt/lib/builtins/ppc/gcc_qsub.c
@@ -1,12 +1,10 @@
-/* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
- * See https://llvm.org/LICENSE.txt for license information.
- * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
- */
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-/* long double __gcc_qsub(long double x, long double y);
- * This file implements the PowerPC 128-bit double-double add operation.
- * This implementation is shamelessly cribbed from Apple's DDRT, circa 1993(!)
- */
+// long double __gcc_qsub(long double x, long double y);
+// This file implements the PowerPC 128-bit double-double add operation.
+// This implementation is shamelessly cribbed from Apple's DDRT, circa 1993(!)
 
 #include "DD.h"
 
@@ -17,14 +15,14 @@ long double __gcc_qsub(long double x, long double y) {
 
   register double A = dst.s.hi, a = dst.s.lo, B = -src.s.hi, b = -src.s.lo;
 
-  /* If both operands are zero: */
+  // If both operands are zero:
   if ((A == 0.0) && (B == 0.0)) {
     dst.s.hi = A + B;
     dst.s.lo = 0.0;
     return dst.ld;
   }
 
-  /* If either operand is NaN or infinity: */
+  // If either operand is NaN or infinity:
   const doublebits abits = {.d = A};
   const doublebits bbits = {.d = B};
   if ((((uint32_t)(abits.x >> 32) & infinityHi) == infinityHi) ||
@@ -34,9 +32,9 @@ long double __gcc_qsub(long double x, long double y) {
     return dst.ld;
   }
 
-  /* If the computation overflows: */
-  /* This may be playing things a little bit fast and loose, but it will do for
-   * a start. */
+  // If the computation overflows:
+  // This may be playing things a little bit fast and loose, but it will do for
+  // a start.
   const double testForOverflow = A + (B + (a + b));
   const doublebits testbits = {.d = testForOverflow};
   if (((uint32_t)(testbits.x >> 32) & infinityHi) == infinityHi) {
diff --git a/compiler-rt/lib/builtins/ppc/multc3.c b/compiler-rt/lib/builtins/ppc/multc3.c
index 40b0d60e6ad..f1fd6816d6c 100644
--- a/compiler-rt/lib/builtins/ppc/multc3.c
+++ b/compiler-rt/lib/builtins/ppc/multc3.c
@@ -1,7 +1,6 @@
-/* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
- * See https://llvm.org/LICENSE.txt for license information.
- * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
- */
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 #include "../int_math.h"
 #include "DD.h"