[PATCH] D65298: [DivRemPairs] Handling for expanded-form rem - recomposition (PR42673)

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

Reduced:

  $ cat zz.ll 
  target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
  target triple = "x86_64-unknown-linux-gnu"
  
  define i32 @d(i32 %X, i32 %Y, i32 %Z) {
  bb:
    %t0 = mul nsw i32 %Z, %Y
    %t1 = sdiv i32 %X, %t0
    %t2 = mul nsw i32 %t0, %t1
    %t3 = sub nsw i32 %X, %t2
    %t4 = sdiv i32 %t3, %Y
    %t5 = mul nsw i32 %t4, %Y
    %t6 = sub nsw i32 %t3, %t5
    ret i32 %t6
  }
  $ /builddirs/llvm-project/build-Clang8-unknown/bin/opt -div-rem-pairs zz.ll -o - -S 
  Only PHI nodes may reference their own value!
    %t6 = srem i32 %t6, %Y
  in function d
  LLVM ERROR: Broken function found, compilation aborted!
  $ /builddirs/llvm-project/build-Clang8-unknown/bin/opt -instcombine zz.ll -o - -S 
  ; ModuleID = 'zz.ll'
  source_filename = "zz.ll"
  target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
  target triple = "x86_64-unknown-linux-gnu"
  
  define i32 @d(i32 %X, i32 %Y, i32 %Z) {
  bb:
    %t0 = mul nsw i32 %Z, %Y
    %0 = srem i32 %X, %t0
    %1 = srem i32 %0, %Y
    ret i32 %1
  }


Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D65298/new/

https://reviews.llvm.org/D65298