[NFC][compiler-rt] Factor out __mulo[sdt]i4 implementations to .inc file

The existing implementations are almost identical except for width of the
integer type.

Factor them out to int_mulo_impl.inc for better maintainability.

This patch is almost identical to D86277.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D86289

Author: atrosinenko

compiler-rt/lib/builtins/int_mulo_impl.inc

@@ -0,0 +1,49 @@
+//===-- int_mulo_impl.inc - Implement __mulo[sdt]i4 ---------------*- C -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Helper used by __mulosi4, __mulodi4 and __muloti4.
+//
+//===----------------------------------------------------------------------===//
+
+#include "int_lib.h"
+
+// Returns: a * b
+
+// Effects: sets *overflow to 1  if a * b overflows
+
+static __inline fixint_t __muloXi4(fixint_t a, fixint_t b, int *overflow) {
+  const int N = (int)(sizeof(fixint_t) * CHAR_BIT);
+  const fixint_t MIN = (fixint_t)1 << (N - 1);
+  const fixint_t MAX = ~MIN;
+  *overflow = 0;
+  fixint_t result = a * b;
+  if (a == MIN) {
+    if (b != 0 && b != 1)
+      *overflow = 1;
+    return result;
+  }
+  if (b == MIN) {
+    if (a != 0 && a != 1)
+      *overflow = 1;
+    return result;
+  }
+  fixint_t sa = a >> (N - 1);
+  fixint_t abs_a = (a ^ sa) - sa;
+  fixint_t sb = b >> (N - 1);
+  fixint_t abs_b = (b ^ sb) - sb;
+  if (abs_a < 2 || abs_b < 2)
+    return result;
+  if (sa == sb) {
+    if (abs_a > MAX / abs_b)
+      *overflow = 1;
+  } else {
+    if (abs_a > MIN / -abs_b)
+      *overflow = 1;
+  }
+  return result;
+}

compiler-rt/lib/builtins/mulodi4.c

@@ -10,40 +10,13 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "int_lib.h"
+#define fixint_t di_int
+#include "int_mulo_impl.inc"
 
 // Returns: a * b
 
 // Effects: sets *overflow to 1  if a * b overflows
 
 COMPILER_RT_ABI di_int __mulodi4(di_int a, di_int b, int *overflow) {
-  const int N = (int)(sizeof(di_int) * CHAR_BIT);
-  const di_int MIN = (di_int)1 << (N - 1);
-  const di_int MAX = ~MIN;
-  *overflow = 0;
-  di_int result = a * b;
-  if (a == MIN) {
-    if (b != 0 && b != 1)
-      *overflow = 1;
-    return result;
-  }
-  if (b == MIN) {
-    if (a != 0 && a != 1)
-      *overflow = 1;
-    return result;
-  }
-  di_int sa = a >> (N - 1);
-  di_int abs_a = (a ^ sa) - sa;
-  di_int sb = b >> (N - 1);
-  di_int abs_b = (b ^ sb) - sb;
-  if (abs_a < 2 || abs_b < 2)
-    return result;
-  if (sa == sb) {
-    if (abs_a > MAX / abs_b)
-      *overflow = 1;
-  } else {
-    if (abs_a > MIN / -abs_b)
-      *overflow = 1;
-  }
-  return result;
+  return __muloXi4(a, b, overflow);
 }

compiler-rt/lib/builtins/mulosi4.c

@@ -10,40 +10,13 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "int_lib.h"
+#define fixint_t si_int
+#include "int_mulo_impl.inc"
 
 // Returns: a * b
 
 // Effects: sets *overflow to 1  if a * b overflows
 
 COMPILER_RT_ABI si_int __mulosi4(si_int a, si_int b, int *overflow) {
-  const int N = (int)(sizeof(si_int) * CHAR_BIT);
-  const si_int MIN = (si_int)1 << (N - 1);
-  const si_int MAX = ~MIN;
-  *overflow = 0;
-  si_int result = a * b;
-  if (a == MIN) {
-    if (b != 0 && b != 1)
-      *overflow = 1;
-    return result;
-  }
-  if (b == MIN) {
-    if (a != 0 && a != 1)
-      *overflow = 1;
-    return result;
-  }
-  si_int sa = a >> (N - 1);
-  si_int abs_a = (a ^ sa) - sa;
-  si_int sb = b >> (N - 1);
-  si_int abs_b = (b ^ sb) - sb;
-  if (abs_a < 2 || abs_b < 2)
-    return result;
-  if (sa == sb) {
-    if (abs_a > MAX / abs_b)
-      *overflow = 1;
-  } else {
-    if (abs_a > MIN / -abs_b)
-      *overflow = 1;
-  }
-  return result;
+  return __muloXi4(a, b, overflow);
 }

compiler-rt/lib/builtins/muloti4.c

@@ -18,36 +18,11 @@
 
 // Effects: sets *overflow to 1  if a * b overflows
 
+#define fixint_t ti_int
+#include "int_mulo_impl.inc"
+
 COMPILER_RT_ABI ti_int __muloti4(ti_int a, ti_int b, int *overflow) {
-  const int N = (int)(sizeof(ti_int) * CHAR_BIT);
-  const ti_int MIN = (ti_int)1 << (N - 1);
-  const ti_int MAX = ~MIN;
-  *overflow = 0;
-  ti_int result = a * b;
-  if (a == MIN) {
-    if (b != 0 && b != 1)
-      *overflow = 1;
-    return result;
-  }
-  if (b == MIN) {
-    if (a != 0 && a != 1)
-      *overflow = 1;
-    return result;
-  }
-  ti_int sa = a >> (N - 1);
-  ti_int abs_a = (a ^ sa) - sa;
-  ti_int sb = b >> (N - 1);
-  ti_int abs_b = (b ^ sb) - sb;
-  if (abs_a < 2 || abs_b < 2)
-    return result;
-  if (sa == sb) {
-    if (abs_a > MAX / abs_b)
-      *overflow = 1;
-  } else {
-    if (abs_a > MIN / -abs_b)
-      *overflow = 1;
-  }
-  return result;
+  return __muloXi4(a, b, overflow);
 }
 
 #endif // CRT_HAS_128BIT