mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-15 20:29:48 +00:00
19 lines
774 B
C
19 lines
774 B
C
|
// 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
|