| ; RUN: opt -S -instcombine < %s | FileCheck %s |
| |
| ; https://llvm.org/bugs/show_bug.cgi?id=25900 |
| ; An arithmetic shift right of a power of two is not a power |
| ; of two if the original value is the sign bit. Therefore, |
| ; we can't transform the sdiv into a udiv. |
| |
| define i32 @pr25900(i32 %d) { |
| %and = and i32 %d, -2147483648 |
| ; The next 3 lines prevent another fold from masking the bug. |
| %ext = zext i32 %and to i64 |
| %or = or i64 %ext, 4294967296 |
| %trunc = trunc i64 %or to i32 |
| %ashr = ashr exact i32 %trunc, 31 |
| %div = sdiv i32 4, %ashr |
| ret i32 %div |
| |
| ; CHECK: sdiv |
| } |
| |
