llvm/test/Other/constant-fold-gep.ll
Dan Gohman 8ca83b4111 Remove the folding rule
getelementptr (i8* inttoptr (i64 1 to i8*), i32 -1) 
  to
  inttoptr (i64 0 to i8*)
from the VMCore constant folder. It didn't handle sign-extension properly
in the case where the source integer is smaller than a pointer size. And,
it relied on an assumption about sizeof(i8).

The Analysis constant folder still folds these kinds of things; it has
access to TargetData, so it can do them right.

Add a testcase which tests that the VMCore constant folder doesn't
miscompile this, and that the Analysis folder does fold it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94750 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-28 18:08:26 +00:00

85 lines
3.2 KiB
LLVM

; RUN: opt -S -o - < %s | FileCheck --check-prefix=PLAIN %s
; RUN: opt -S -o - -instcombine -globalopt < %s | FileCheck --check-prefix=OPT %s
; The automatic constant folder in opt does not have targetdata access, so
; it can't fold gep arithmetic, in general. However, the constant folder run
; from instcombine and global opt does, and can.
; PLAIN: @G8 = global i8* getelementptr (i8* inttoptr (i32 1 to i8*), i32 -1)
; PLAIN: @G1 = global i1* getelementptr (i1* inttoptr (i32 1 to i1*), i32 -1)
; PLAIN: @F8 = global i8* getelementptr (i8* inttoptr (i32 1 to i8*), i32 -2)
; PLAIN: @F1 = global i1* getelementptr (i1* inttoptr (i32 1 to i1*), i32 -2)
; PLAIN: @H8 = global i8* getelementptr (i8* null, i32 -1)
; PLAIN: @H1 = global i1* getelementptr (i1* null, i32 -1)
; PLAIN: define i8* @goo8() nounwind {
; PLAIN: ret i8* getelementptr (i8* inttoptr (i32 1 to i8*), i32 -1)
; PLAIN: }
; PLAIN: define i1* @goo1() nounwind {
; PLAIN: ret i1* getelementptr (i1* inttoptr (i32 1 to i1*), i32 -1)
; PLAIN: }
; PLAIN: define i8* @foo8() nounwind {
; PLAIN: ret i8* getelementptr (i8* inttoptr (i32 1 to i8*), i32 -2)
; PLAIN: }
; PLAIN: define i1* @foo1() nounwind {
; PLAIN: ret i1* getelementptr (i1* inttoptr (i32 1 to i1*), i32 -2)
; PLAIN: }
; PLAIN: define i8* @hoo8() nounwind {
; PLAIN: ret i8* getelementptr (i8* null, i32 -1)
; PLAIN: }
; PLAIN: define i1* @hoo1() nounwind {
; PLAIN: ret i1* getelementptr (i1* null, i32 -1)
; PLAIN: }
; OPT: @G8 = global i8* null
; OPT: @G1 = global i1* null
; OPT: @F8 = global i8* inttoptr (i64 -1 to i8*)
; OPT: @F1 = global i1* inttoptr (i64 -1 to i1*)
; OPT: @H8 = global i8* inttoptr (i64 -1 to i8*)
; OPT: @H1 = global i1* inttoptr (i64 -1 to i1*)
; OPT: define i8* @goo8() nounwind {
; OPT: ret i8* null
; OPT: }
; OPT: define i1* @goo1() nounwind {
; OPT: ret i1* null
; OPT: }
; OPT: define i8* @foo8() nounwind {
; OPT: ret i8* inttoptr (i64 -1 to i8*)
; OPT: }
; OPT: define i1* @foo1() nounwind {
; OPT: ret i1* inttoptr (i64 -1 to i1*)
; OPT: }
; OPT: define i8* @hoo8() nounwind {
; OPT: ret i8* inttoptr (i64 -1 to i8*)
; OPT: }
; OPT: define i1* @hoo1() nounwind {
; OPT: ret i1* inttoptr (i64 -1 to i1*)
; OPT: }
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64"
@G8 = global i8* getelementptr (i8* inttoptr (i32 1 to i8*), i32 -1)
@G1 = global i1* getelementptr (i1* inttoptr (i32 1 to i1*), i32 -1)
@F8 = global i8* getelementptr (i8* inttoptr (i32 1 to i8*), i32 -2)
@F1 = global i1* getelementptr (i1* inttoptr (i32 1 to i1*), i32 -2)
@H8 = global i8* getelementptr (i8* inttoptr (i32 0 to i8*), i32 -1)
@H1 = global i1* getelementptr (i1* inttoptr (i32 0 to i1*), i32 -1)
define i8* @goo8() nounwind {
ret i8* getelementptr (i8* inttoptr (i32 1 to i8*), i32 -1)
}
define i1* @goo1() nounwind {
ret i1* getelementptr (i1* inttoptr (i32 1 to i1*), i32 -1)
}
define i8* @foo8() nounwind {
ret i8* getelementptr (i8* inttoptr (i32 1 to i8*), i32 -2)
}
define i1* @foo1() nounwind {
ret i1* getelementptr (i1* inttoptr (i32 1 to i1*), i32 -2)
}
define i8* @hoo8() nounwind {
ret i8* getelementptr (i8* inttoptr (i32 0 to i8*), i32 -1)
}
define i1* @hoo1() nounwind {
ret i1* getelementptr (i1* inttoptr (i32 0 to i1*), i32 -1)
}