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Add test cases for PRE w/volatile loads

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These tests check that the combination of 227110 (cross block query inst) and 227112 (volatile load semantics) work together properly to allow PRE in cases where a loop contains a volatile access.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227146 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Philip Reames 2015-01-26 22:40:44 +00:00
parent 44513da617
commit c1beae0d42
1 changed files with 82 additions and 0 deletions
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82
test/Transforms/GVN/volatile.ll
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@ -73,3 +73,85 @@ entry:
ret i32 %add
}
; Does cross block redundancy elimination work with volatiles?
define i32 @test6(i32* noalias nocapture %p, i32* noalias nocapture %q) {
; CHECK-LABEL: test6
; CHECK: %y1 = load i32* %p
; CHECK-LABEL: header
; CHECK: %x = load volatile i32* %q
; CHECK-NEXT: %add = sub i32 %y1, %x
entry:
%y1 = load i32* %p
call void @use(i32 %y1)
br label %header
header:
%x = load volatile i32* %q
%y = load i32* %p
%add = sub i32 %y, %x
%cnd = icmp eq i32 %add, 0
br i1 %cnd, label %exit, label %header
exit:
ret i32 %add
}
; Does cross block PRE work with volatiles?
define i32 @test7(i1 %c, i32* noalias nocapture %p, i32* noalias nocapture %q) {
; CHECK-LABEL: test7
; CHECK-LABEL: entry.header_crit_edge:
; CHECK: %y.pre = load i32* %p
; CHECK-LABEL: skip:
; CHECK: %y1 = load i32* %p
; CHECK-LABEL: header:
; CHECK: %y = phi i32
; CHECK-NEXT: %x = load volatile i32* %q
; CHECK-NEXT: %add = sub i32 %y, %x
entry:
br i1 %c, label %header, label %skip
skip:
%y1 = load i32* %p
call void @use(i32 %y1)
br label %header
header:
%x = load volatile i32* %q
%y = load i32* %p
%add = sub i32 %y, %x
%cnd = icmp eq i32 %add, 0
br i1 %cnd, label %exit, label %header
exit:
ret i32 %add
}
; Another volatile PRE case - two paths through a loop
; load in preheader, one path read only, one not
define i32 @test8(i1 %b, i1 %c, i32* noalias %p, i32* noalias %q) {
; CHECK-LABEL: test8
; CHECK-LABEL: entry
; CHECK: %y1 = load i32* %p
; CHECK-LABEL: header:
; CHECK: %y = phi i32
; CHECK-NEXT: %x = load volatile i32* %q
; CHECK-NOT: load
; CHECK-LABEL: skip.header_crit_edge:
; CHECK: %y.pre = load i32* %p
entry:
%y1 = load i32* %p
call void @use(i32 %y1)
br label %header
header:
%x = load volatile i32* %q
%y = load i32* %p
call void @use(i32 %y)
br i1 %b, label %skip, label %header
skip:
; escaping the arguments is explicitly required since we marked
; them noalias
call void @clobber(i32* %p, i32* %q)
br i1 %c, label %header, label %exit
exit:
%add = sub i32 %y, %x
ret i32 %add
}
declare void @use(i32) readonly
declare void @clobber(i32* %p, i32* %q)