Wael Yehia 0952cf5bbb [InstCombine] decomposeSimpleLinearExpr should bail out on negative operands.
InstCombine tries to rewrite

  %prod = mul nsw i64 %X,   Scale
  %acc = add nsw i64 %prod,   Offset
  %0 = alloca i8, i64 %acc, align 4
  %1 = bitcast i8* %0 to i32*
  Use ( %1 )

into

  %prod = mul nsw i64 %X,   Scale/4
  %acc = add nsw i64 %prod,   Offset/4
  %0 = alloca i32, i64 %acc, align 4
  Use (%0)

But it assumes Scale is unsigned, and performs an unsigned division.
So we should bail out if Scale cannot be interpreted as an unsigned safely.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D126546
2022-06-08 00:57:25 +00:00
..
2022-04-25 12:53:39 +02:00

This directory contains test cases for the instcombine transformation.  The
dated tests are actual bug tests, whereas the named tests are used to test
for features that the this pass should be capable of performing.