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When attempting to sign-extend an addrec by interpreting 

the step value as unsigned, the start value and the addrec
itself still need to be treated as signed.

llvm-svn: 77078
This commit is contained in:
Dan Gohman 2009-07-25 16:03:30 +00:00
parent b7e6a3f527
commit 534d66a426
2 changed files with 76 additions and 2 deletions
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4
llvm/lib/Analysis/ScalarEvolution.cpp
View File

@ -923,10 +923,10 @@ const SCEV *ScalarEvolution::getSignExtendExpr(const SCEV *Op,
getTruncateOrZeroExtend(Step, Start->getType()));
Add = getAddExpr(Start, UMul);
OperandExtendedAdd =
getAddExpr(getZeroExtendExpr(Start, WideTy),
getAddExpr(getSignExtendExpr(Start, WideTy),
getMulExpr(getZeroExtendExpr(CastedMaxBECount, WideTy),
getZeroExtendExpr(Step, WideTy)));
if (getZeroExtendExpr(Add, WideTy) == OperandExtendedAdd)
if (getSignExtendExpr(Add, WideTy) == OperandExtendedAdd)
// Return the expression with the addrec on the outside.
return getAddRecExpr(getSignExtendExpr(Start, Ty),
getZeroExtendExpr(Step, Ty),

74
llvm/test/Analysis/ScalarEvolution/sext-iv-2.ll Normal file
View File

@ -0,0 +1,74 @@
; RUN: llvm-as < %s | opt -analyze -scalar-evolution -disable-output | FileCheck %s
; CHECK: %tmp3 = sext i8 %tmp2 to i32
; CHECK: --> (sext i8 {0,+,1}<bb1> to i32) Exits: -1
; CHECK: %tmp4 = mul i32 %tmp3, %i.02
; CHECK: --> ((sext i8 {0,+,1}<bb1> to i32) * {0,+,1}<bb>) Exits: {0,+,-1}<bb>
; These sexts are not foldable.
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64"
@table = common global [32 x [256 x i32]] zeroinitializer, align 32 ; <[32 x [256 x i32]]*> [#uses=2]
define i32 @main() nounwind {
entry:
br i1 false, label %bb5, label %bb.nph3
bb.nph3: ; preds = %entry
br label %bb
bb: ; preds = %bb4, %bb.nph3
%i.02 = phi i32 [ %tmp10, %bb4 ], [ 0, %bb.nph3 ] ; <i32> [#uses=3]
br i1 false, label %bb3, label %bb.nph
bb.nph: ; preds = %bb
br label %bb1
bb1: ; preds = %bb2, %bb.nph
%j.01 = phi i32 [ %tmp8, %bb2 ], [ 0, %bb.nph ] ; <i32> [#uses=3]
%tmp2 = trunc i32 %j.01 to i8 ; <i8> [#uses=1]
%tmp3 = sext i8 %tmp2 to i32 ; <i32> [#uses=1]
%tmp4 = mul i32 %tmp3, %i.02 ; <i32> [#uses=1]
%tmp5 = sext i32 %i.02 to i64 ; <i64> [#uses=1]
%tmp6 = sext i32 %j.01 to i64 ; <i64> [#uses=1]
%tmp7 = getelementptr [32 x [256 x i32]]* @table, i64 0, i64 %tmp5, i64 %tmp6 ; <i32*> [#uses=1]
store i32 %tmp4, i32* %tmp7, align 4
%tmp8 = add i32 %j.01, 1 ; <i32> [#uses=2]
br label %bb2
bb2: ; preds = %bb1
%phitmp1 = icmp sgt i32 %tmp8, 255 ; <i1> [#uses=1]
br i1 %phitmp1, label %bb2.bb3_crit_edge, label %bb1
bb2.bb3_crit_edge: ; preds = %bb2
br label %bb3
bb3: ; preds = %bb2.bb3_crit_edge, %bb
%tmp10 = add i32 %i.02, 1 ; <i32> [#uses=2]
br label %bb4
bb4: ; preds = %bb3
%phitmp = icmp sgt i32 %tmp10, 31 ; <i1> [#uses=1]
br i1 %phitmp, label %bb4.bb5_crit_edge, label %bb
bb4.bb5_crit_edge: ; preds = %bb4
br label %bb5
bb5: ; preds = %bb4.bb5_crit_edge, %entry
%tmp12 = load i32* getelementptr ([32 x [256 x i32]]* @table, i64 0, i64 9, i64 132), align 16 ; <i32> [#uses=1]
%tmp13 = icmp eq i32 %tmp12, -1116 ; <i1> [#uses=1]
br i1 %tmp13, label %bb7, label %bb6
bb6: ; preds = %bb5
call void @abort() noreturn nounwind
unreachable
bb7: ; preds = %bb5
br label %return
return: ; preds = %bb7
ret i32 0
}
declare void @abort() noreturn nounwind