1 files changed, 72 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/builtins/int_to_fp_impl.inc b/contrib/llvm-project/compiler-rt/lib/builtins/int_to_fp_impl.inc
new file mode 100644
index 000000000000..51f76fd76d80
--- /dev/null
+++ b/contrib/llvm-project/compiler-rt/lib/builtins/int_to_fp_impl.inc
@@ -0,0 +1,72 @@
+//===-- int_to_fp_impl.inc - integer to floating point conversion ---------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Thsi file implements a generic conversion from an integer type to an
+// IEEE-754 floating point type, allowing a common implementation to be hsared
+// without copy and paste.
+//
+//===----------------------------------------------------------------------===//
+
+#include "int_to_fp.h"
+
+static __inline dst_t __floatXiYf__(src_t a) {
+  if (a == 0)
+    return 0.0;
+
+  enum {
+    dstMantDig = dstSigBits + 1,
+    srcBits = sizeof(src_t) * CHAR_BIT,
+    srcIsSigned = ((src_t)-1) < 0,
+  };
+
+  const src_t s = srcIsSigned ? a >> (srcBits - 1) : 0;
+
+  a = (usrc_t)(a ^ s) - s;
+  int sd = srcBits - clzSrcT(a);         // number of significant digits
+  int e = sd - 1;                        // exponent
+  if (sd > dstMantDig) {
+    //  start:  0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx
+    //  finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR
+    //                                                12345678901234567890123456
+    //  1 = msb 1 bit
+    //  P = bit dstMantDig-1 bits to the right of 1
+    //  Q = bit dstMantDig bits to the right of 1
+    //  R = "or" of all bits to the right of Q
+    if (sd == dstMantDig + 1) {
+      a <<= 1;
+    } else if (sd == dstMantDig + 2) {
+      // Do nothing.
+    } else {
+      a = ((usrc_t)a >> (sd - (dstMantDig + 2))) |
+          ((a & ((usrc_t)(-1) >> ((srcBits + dstMantDig + 2) - sd))) != 0);
+    }
+    // finish:
+    a |= (a & 4) != 0; // Or P into R
+    ++a;               // round - this step may add a significant bit
+    a >>= 2;           // dump Q and R
+    // a is now rounded to dstMantDig or dstMantDig+1 bits
+    if (a & ((usrc_t)1 << dstMantDig)) {
+      a >>= 1;
+      ++e;
+    }
+    // a is now rounded to dstMantDig bits
+  } else {
+    a <<= (dstMantDig - sd);
+    // a is now rounded to dstMantDig bits
+  }
+  const int dstBits = sizeof(dst_t) * CHAR_BIT;
+  const dst_rep_t dstSignMask = DST_REP_C(1) << (dstBits - 1);
+  const int dstExpBits = dstBits - dstSigBits - 1;
+  const int dstExpBias = (1 << (dstExpBits - 1)) - 1;
+  const dst_rep_t dstSignificandMask = (DST_REP_C(1) << dstSigBits) - 1;
+  // Combine sign, exponent, and mantissa.
+  const dst_rep_t result = ((dst_rep_t)s & dstSignMask) |
+                           ((dst_rep_t)(e + dstExpBias) << dstSigBits) |
+                           ((dst_rep_t)(a) & dstSignificandMask);
+  return dstFromRep(result);
+}