This improves the variable use weight by taking into account use in loops. It
further improves spec2k performance and fixes the regression in ammp. Loops are
identified using an extension to Tarjan's algorithm.
BUG=
R=stichnot@chromium.org
Review URL: https://codereview.chromium.org/1318553003.
diff --git a/src/IceUtils.h b/src/IceUtils.h
index 6d65ade..f07a566 100644
--- a/src/IceUtils.h
+++ b/src/IceUtils.h
@@ -70,6 +70,18 @@
(X < 0 && Y < 0 && (X < std::numeric_limits<T>::min() - Y)));
}
+ /// Adds x to y and stores the result in sum. Returns true if the addition
+ /// overflowed.
+ static inline bool add_overflow(uint32_t x, uint32_t y, uint32_t *sum) {
+ static_assert(std::is_same<uint32_t, unsigned>::value, "Must match type");
+#if __has_builtin(__builtin_uadd_overflow)
+ return __builtin_uadd_overflow(x, y, sum);
+#else
+ *sum = x + y;
+ return WouldOverflowAdd(x, y);
+#endif
+ }
+
/// Return true if X is already aligned by N, where N is a power of 2.
template <typename T> static inline bool IsAligned(T X, intptr_t N) {
assert(llvm::isPowerOf2_64(N));
