diff options
Diffstat (limited to 'test/FrontendC/2010-07-27-MinNoFoldConst.c')
| -rw-r--r-- | test/FrontendC/2010-07-27-MinNoFoldConst.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/test/FrontendC/2010-07-27-MinNoFoldConst.c b/test/FrontendC/2010-07-27-MinNoFoldConst.c new file mode 100644 index 000000000000..7cd8b4c43764 --- /dev/null +++ b/test/FrontendC/2010-07-27-MinNoFoldConst.c @@ -0,0 +1,18 @@ +// RUN: %llvmgcc -S %s -o - | FileCheck %s +extern int printf(const char *, ...); +static void bad(unsigned int v1, unsigned int v2) { + printf("%u\n", 1631381461u * (((v2 - 1273463329u <= v1 - 1273463329u) ? v2 : v1) - 1273463329u) + 121322179u); +} +// Radar 8198362 +// GCC FE wants to convert the above to +// 1631381461u * MIN(v2 - 1273463329u, v1 - 1273463329u) +// and then to +// MIN(1631381461u * v2 - 4047041419, 1631381461u * v1 - 4047041419) +// +// 1631381461u * 1273463329u = 2077504466193943669, but 32-bit overflow clips +// this to 4047041419. This breaks the comparision implicit in the MIN(). +// Two multiply operations suggests the bad optimization is happening; +// one multiplication, after the MIN(), is correct. +// CHECK: mul +// CHECK-NOT: mul +// CHECK: ret |