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llvm-mirror/test/CodeGen/ARM/2013-05-05-IfConvertBug.ll
Quentin Colombet 83197eea3a Fix a bug in IfConverter with nested predicates.
Prior to this patch, IfConverter may widen the cases where a sequence of
instructions were executed because of the way it uses nested predicates. This
result in incorrect execution.

For instance, Let A be a basic block that flows conditionally into B and B be a
predicated block.
B can be predicated with A.BrToBPredicate into A iff B.Predicate is less
"permissive" than A.BrToBPredicate, i.e., iff A.BrToBPredicate subsumes
B.Predicate.

The IfConverter was checking the opposite: B.Predicate subsumes
A.BrToBPredicate.

<rdar://problem/14379453>

llvm-svn: 187071
2013-07-24 20:20:37 +00:00

131 lines
3.7 KiB
LLVM

; RUN: llc < %s -mtriple=thumbv7-apple-ios -mcpu=cortex-a8 | FileCheck %s
; rdar://13782395
define i32 @t1(i32 %a, i32 %b, i8** %retaddr) {
; CHECK-LABEL: t1:
; CHECK: Block address taken
; CHECK-NOT: Address of block that was removed by CodeGen
store i8* blockaddress(@t1, %cond_true), i8** %retaddr
%tmp2 = icmp eq i32 %a, 0
br i1 %tmp2, label %cond_false, label %cond_true
cond_true:
%tmp5 = add i32 %b, 1
ret i32 %tmp5
cond_false:
%tmp7 = add i32 %b, -1
ret i32 %tmp7
}
define i32 @t2(i32 %a, i32 %b, i32 %c, i32 %d, i8** %retaddr) {
; CHECK-LABEL: t2:
; CHECK: Block address taken
; CHECK: %cond_true
; CHECK: add
; CHECK: bx lr
store i8* blockaddress(@t2, %cond_true), i8** %retaddr
%tmp2 = icmp sgt i32 %c, 10
%tmp5 = icmp slt i32 %d, 4
%tmp8 = and i1 %tmp5, %tmp2
%tmp13 = add i32 %b, %a
br i1 %tmp8, label %cond_true, label %UnifiedReturnBlock
cond_true:
%tmp15 = add i32 %tmp13, %c
%tmp1821 = sub i32 %tmp15, %d
ret i32 %tmp1821
UnifiedReturnBlock:
ret i32 %tmp13
}
define hidden fastcc void @t3(i8** %retaddr) {
; CHECK-LABEL: t3:
; CHECK: Block address taken
; CHECK-NOT: Address of block that was removed by CodeGen
bb:
store i8* blockaddress(@t3, %KBBlockZero_return_1), i8** %retaddr
br i1 undef, label %bb77, label %bb7.i
bb7.i: ; preds = %bb35
br label %bb2.i
KBBlockZero_return_1: ; preds = %KBBlockZero.exit
unreachable
KBBlockZero_return_0: ; preds = %KBBlockZero.exit
unreachable
bb77: ; preds = %bb26, %bb12, %bb
ret void
bb2.i: ; preds = %bb6.i350, %bb7.i
br i1 undef, label %bb6.i350, label %KBBlockZero.exit
bb6.i350: ; preds = %bb2.i
br label %bb2.i
KBBlockZero.exit: ; preds = %bb2.i
indirectbr i8* undef, [label %KBBlockZero_return_1, label %KBBlockZero_return_0]
}
; If-converter was checking for the wrong predicate subsumes pattern when doing
; nested predicates.
; E.g., Let A be a basic block that flows conditionally into B and B be a
; predicated block.
; B can be predicated with A.BrToBPredicate into A iff B.Predicate is less
; "permissive" than A.BrToBPredicate, i.e., iff A.BrToBPredicate subsumes
; B.Predicate.
; <rdar://problem/14379453>
; Hard-coded registers comes from the ABI.
; CHECK: wrapDistance:
; CHECK: cmp r1, #59
; CHECK-NEXT: itt le
; CHECK-NEXT: suble r0, r2, #1
; CHECK-NEXT: bxle lr
; CHECK-NEXT: subs [[REG:r[0-9]+]], #120
; CHECK-NEXT: cmp [[REG]], r1
; CHECK-NOT: it lt
; CHECK-NEXT: bge [[LABEL:.+]]
; Next BB
; CHECK-NOT: cmplt
; CHECK: cmp r0, #119
; CHECK-NEXT: itt le
; CHECK-NEXT: addle r0, r1, #1
; CHECK-NEXT: bxle lr
; Next BB
; CHECK: [[LABEL]]:
; CHECK-NEXT: subs r0, r1, r0
; CHECK-NEXT: bx lr
define i32 @wrapDistance(i32 %tx, i32 %sx, i32 %w) {
entry:
%cmp = icmp slt i32 %sx, 60
br i1 %cmp, label %if.then, label %if.else
if.then: ; preds = %entry
%sub = add nsw i32 %w, -1
br label %return
if.else: ; preds = %entry
%sub1 = add nsw i32 %w, -120
%cmp2 = icmp slt i32 %sub1, %sx
%cmp3 = icmp slt i32 %tx, 120
%or.cond = and i1 %cmp2, %cmp3
br i1 %or.cond, label %if.then4, label %if.end5
if.then4: ; preds = %if.else
%add = add nsw i32 %sx, 1
br label %return
if.end5: ; preds = %if.else
%sub6 = sub nsw i32 %sx, %tx
br label %return
return: ; preds = %if.end5, %if.then4, %if.then
%retval.0 = phi i32 [ %sub, %if.then ], [ %add, %if.then4 ], [ %sub6, %if.end5 ]
ret i32 %retval.0
}