| Stuart Hastings | 3c73a6b | 2010-07-27 23:15:25 +0000 | [diff] [blame] | 1 | // RUN: %llvmgcc -S %s -o - | FileCheck %s |
| 2 | extern int printf(const char *, ...); |
| 3 | static void bad(unsigned int v1, unsigned int v2) { |
| 4 | printf("%u\n", 1631381461u * (((v2 - 1273463329u <= v1 - 1273463329u) ? v2 : v1) - 1273463329u) + 121322179u); |
| 5 | } |
| 6 | // Radar 8198362 |
| 7 | // GCC FE wants to convert the above to |
| 8 | // 1631381461u * MIN(v2 - 1273463329u, v1 - 1273463329u) |
| 9 | // and then to |
| 10 | // MIN(1631381461u * v2 - 4047041419, 1631381461u * v1 - 4047041419) |
| 11 | // |
| 12 | // 1631381461u * 1273463329u = 2077504466193943669, but 32-bit overflow clips |
| 13 | // this to 4047041419. This breaks the comparision implicit in the MIN(). |
| 14 | // Two multiply operations suggests the bad optimization is happening; |
| 15 | // one multiplication, after the MIN(), is correct. |
| 16 | // CHECK: mul |
| 17 | // CHECK-NOT: mul |
| 18 | // CHECK: ret |