calloc-load-removal.ll 835 B

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  1. ; RUN: opt -S -basicaa -gvn < %s | FileCheck %s
  2. ; RUN: opt -S -basicaa -gvn -disable-simplify-libcalls < %s | FileCheck %s -check-prefix=CHECK_NO_LIBCALLS
  3. ; Check that loads from calloc are recognized as being zero.
  4. target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
  5. ; Function Attrs: nounwind uwtable
  6. define i32 @test1() {
  7. %1 = tail call noalias i8* @calloc(i64 1, i64 4)
  8. %2 = bitcast i8* %1 to i32*
  9. ; This load is trivially constant zero
  10. %3 = load i32, i32* %2, align 4
  11. ret i32 %3
  12. ; CHECK-LABEL: @test1(
  13. ; CHECK-NOT: %3 = load i32, i32* %2, align 4
  14. ; CHECK: ret i32 0
  15. ; CHECK_NO_LIBCALLS-LABEL: @test1(
  16. ; CHECK_NO_LIBCALLS: load
  17. ; CHECK_NO_LIBCALLS: ret i32 %
  18. }
  19. declare noalias i8* @calloc(i64, i64)