[compiler-rt] Avoid signed shift overflow in __muloXi4 and __mulvXi3

When compiling compiler-rt with -fsanitize=undefined and running testcases you
end up with the following warning:

UBSan: int_mulo_impl.inc:21:36: left shift of 1 by 63 places cannot be represented in type 'di_int' (aka 'long long')

This can be avoided by simply doing the shift in a matching unsigned variant of
the type.

The same kind of pattern seems to exist in int_mulv_impl.inc

This was found in an out of tree target.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D145556

compiler-rt/lib/builtins/int_mulo_impl.inc

@@ -18,7 +18,7 @@
 
 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 MIN = (fixint_t)((fixuint_t)1 << (N - 1));
   const fixint_t MAX = ~MIN;
   *overflow = 0;
   fixint_t result = a * b;

compiler-rt/lib/builtins/int_mulv_impl.inc

@@ -18,7 +18,7 @@
 
 static __inline fixint_t __mulvXi3(fixint_t a, fixint_t b) {
   const int N = (int)(sizeof(fixint_t) * CHAR_BIT);
-  const fixint_t MIN = (fixint_t)1 << (N - 1);
+  const fixint_t MIN = (fixint_t)((fixuint_t)1 << (N - 1));
   const fixint_t MAX = ~MIN;
   if (a == MIN) {
     if (b == 0 || b == 1)

compiler-rt/lib/builtins/mulodi4.c

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #define fixint_t di_int
+#define fixuint_t du_int
 #include "int_mulo_impl.inc"
 
 // Returns: a * b

compiler-rt/lib/builtins/mulosi4.c

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #define fixint_t si_int
+#define fixuint_t su_int
 #include "int_mulo_impl.inc"
 
 // Returns: a * b

compiler-rt/lib/builtins/muloti4.c

@@ -19,6 +19,7 @@
 // Effects: sets *overflow to 1  if a * b overflows
 
 #define fixint_t ti_int
+#define fixuint_t tu_int
 #include "int_mulo_impl.inc"
 
 COMPILER_RT_ABI ti_int __muloti4(ti_int a, ti_int b, int *overflow) {

compiler-rt/lib/builtins/mulvdi3.c

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #define fixint_t di_int
+#define fixuint_t du_int
 #include "int_mulv_impl.inc"
 
 // Returns: a * b

compiler-rt/lib/builtins/mulvsi3.c

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #define fixint_t si_int
+#define fixuint_t su_int
 #include "int_mulv_impl.inc"
 
 // Returns: a * b

compiler-rt/lib/builtins/mulvti3.c

@@ -19,6 +19,7 @@
 // Effects: aborts if a * b overflows
 
 #define fixint_t ti_int
+#define fixuint_t tu_int
 #include "int_mulv_impl.inc"
 
 COMPILER_RT_ABI ti_int __mulvti3(ti_int a, ti_int b) { return __mulvXi3(a, b); }