llvm-6502/test/Transforms/Inline/inline_constprop.ll
Chandler Carruth 961e1acfb2 Fix PR13412, a nasty miscompile due to the interleaved
instsimplify+inline strategy.

The crux of the problem is that instsimplify was reasonably relying on
an invariant that is true within any single function, but is no longer
true mid-inline the way we use it. This invariant is that an argument
pointer != a local (alloca) pointer.

The fix is really light weight though, and allows instsimplify to be
resiliant to these situations: when checking the relation ships to
function arguments, ensure that the argumets come from the same
function. If they come from different functions, then none of these
assumptions hold. All credit to Benjamin Kramer for coming up with this
clever solution to the problem.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161410 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-07 10:59:59 +00:00

175 lines
4.1 KiB
LLVM

; RUN: opt < %s -inline -inline-threshold=20 -S | FileCheck %s
define internal i32 @callee1(i32 %A, i32 %B) {
%C = sdiv i32 %A, %B
ret i32 %C
}
define i32 @caller1() {
; CHECK: define i32 @caller1
; CHECK-NEXT: ret i32 3
%X = call i32 @callee1( i32 10, i32 3 )
ret i32 %X
}
define i32 @caller2() {
; Check that we can constant-prop through instructions after inlining callee21
; to get constants in the inlined callsite to callee22.
; FIXME: Currently, the threshold is fixed at 20 because we don't perform
; *recursive* cost analysis to realize that the nested call site will definitely
; inline and be cheap. We should eventually do that and lower the threshold here
; to 1.
;
; CHECK: @caller2
; CHECK-NOT: call void @callee2
; CHECK: ret
%x = call i32 @callee21(i32 42, i32 48)
ret i32 %x
}
define i32 @callee21(i32 %x, i32 %y) {
%sub = sub i32 %y, %x
%result = call i32 @callee22(i32 %sub)
ret i32 %result
}
declare i8* @getptr()
define i32 @callee22(i32 %x) {
%icmp = icmp ugt i32 %x, 42
br i1 %icmp, label %bb.true, label %bb.false
bb.true:
; This block musn't be counted in the inline cost.
%x1 = add i32 %x, 1
%x2 = add i32 %x1, 1
%x3 = add i32 %x2, 1
%x4 = add i32 %x3, 1
%x5 = add i32 %x4, 1
%x6 = add i32 %x5, 1
%x7 = add i32 %x6, 1
%x8 = add i32 %x7, 1
ret i32 %x8
bb.false:
ret i32 %x
}
define i32 @caller3() {
; Check that even if the expensive path is hidden behind several basic blocks,
; it doesn't count toward the inline cost when constant-prop proves those paths
; dead.
;
; CHECK: @caller3
; CHECK-NOT: call
; CHECK: ret i32 6
entry:
%x = call i32 @callee3(i32 42, i32 48)
ret i32 %x
}
define i32 @callee3(i32 %x, i32 %y) {
%sub = sub i32 %y, %x
%icmp = icmp ugt i32 %sub, 42
br i1 %icmp, label %bb.true, label %bb.false
bb.true:
%icmp2 = icmp ult i32 %sub, 64
br i1 %icmp2, label %bb.true.true, label %bb.true.false
bb.true.true:
; This block musn't be counted in the inline cost.
%x1 = add i32 %x, 1
%x2 = add i32 %x1, 1
%x3 = add i32 %x2, 1
%x4 = add i32 %x3, 1
%x5 = add i32 %x4, 1
%x6 = add i32 %x5, 1
%x7 = add i32 %x6, 1
%x8 = add i32 %x7, 1
br label %bb.merge
bb.true.false:
; This block musn't be counted in the inline cost.
%y1 = add i32 %y, 1
%y2 = add i32 %y1, 1
%y3 = add i32 %y2, 1
%y4 = add i32 %y3, 1
%y5 = add i32 %y4, 1
%y6 = add i32 %y5, 1
%y7 = add i32 %y6, 1
%y8 = add i32 %y7, 1
br label %bb.merge
bb.merge:
%result = phi i32 [ %x8, %bb.true.true ], [ %y8, %bb.true.false ]
ret i32 %result
bb.false:
ret i32 %sub
}
define i32 @PR13412.main() {
; This is a somewhat complicated three layer subprogram that was reported to
; compute the wrong value for a branch due to assuming that an argument
; mid-inline couldn't be equal to another pointer.
;
; After inlining, the branch should point directly to the exit block, not to
; the intermediate block.
; CHECK: @PR13412.main
; CHECK: br i1 true, label %[[TRUE_DEST:.*]], label %[[FALSE_DEST:.*]]
; CHECK: [[FALSE_DEST]]:
; CHECK-NEXT: call void @PR13412.fail()
; CHECK: [[TRUE_DEST]]:
; CHECK-NEXT: ret i32 0
entry:
%i1 = alloca i64
store i64 0, i64* %i1
%arraydecay = bitcast i64* %i1 to i32*
%call = call i1 @PR13412.first(i32* %arraydecay, i32* %arraydecay)
br i1 %call, label %cond.end, label %cond.false
cond.false:
call void @PR13412.fail()
br label %cond.end
cond.end:
ret i32 0
}
define internal i1 @PR13412.first(i32* %a, i32* %b) {
entry:
%call = call i32* @PR13412.second(i32* %a, i32* %b)
%cmp = icmp eq i32* %call, %b
ret i1 %cmp
}
declare void @PR13412.fail()
define internal i32* @PR13412.second(i32* %a, i32* %b) {
entry:
%sub.ptr.lhs.cast = ptrtoint i32* %b to i64
%sub.ptr.rhs.cast = ptrtoint i32* %a to i64
%sub.ptr.sub = sub i64 %sub.ptr.lhs.cast, %sub.ptr.rhs.cast
%sub.ptr.div = ashr exact i64 %sub.ptr.sub, 2
%cmp = icmp ugt i64 %sub.ptr.div, 1
br i1 %cmp, label %if.then, label %if.end3
if.then:
%0 = load i32* %a
%1 = load i32* %b
%cmp1 = icmp eq i32 %0, %1
br i1 %cmp1, label %return, label %if.end3
if.end3:
br label %return
return:
%retval.0 = phi i32* [ %b, %if.end3 ], [ %a, %if.then ]
ret i32* %retval.0
}