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Simplify some code with no functionality change. Make the test a lot more

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robust against smarter optimizations, using the power of FileCheck.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124081 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2011-01-23 20:06:05 +00:00
parent dd0dfdf8be
commit 76167af9b1
2 changed files with 23 additions and 27 deletions
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16
lib/Analysis/ScalarEvolution.cpp
View File

@ -904,15 +904,11 @@ const SCEV *ScalarEvolution::getZeroExtendExpr(const SCEV *Op,
// so, we should be able to simplify this further.
const SCEV *X = ST->getOperand();
ConstantRange CR = getUnsignedRange(X);
unsigned OrigBits = CR.getBitWidth();
unsigned TruncBits = getTypeSizeInBits(ST->getType());
unsigned NewBits = getTypeSizeInBits(Ty);
if (CR.truncate(TruncBits).zeroExtend(NewBits).contains(
CR.zextOrTrunc(NewBits))) {
if (NewBits > OrigBits) return getZeroExtendExpr(X, Ty);
if (NewBits < OrigBits) return getTruncateExpr(X, Ty);
return X;
}
CR.zextOrTrunc(NewBits)))
return getTruncateOrZeroExtend(X, Ty);
}
// If the input value is a chrec scev, and we can prove that the value
@ -1062,15 +1058,11 @@ const SCEV *ScalarEvolution::getSignExtendExpr(const SCEV *Op,
// so, we should be able to simplify this further.
const SCEV *X = ST->getOperand();
ConstantRange CR = getSignedRange(X);
unsigned OrigBits = CR.getBitWidth();
unsigned TruncBits = getTypeSizeInBits(ST->getType());
unsigned NewBits = getTypeSizeInBits(Ty);
if (CR.truncate(TruncBits).signExtend(NewBits).contains(
CR.sextOrTrunc(NewBits))) {
if (NewBits > OrigBits) return getSignExtendExpr(X, Ty);
if (NewBits < OrigBits) return getTruncateExpr(X, Ty);
return X;
}
CR.sextOrTrunc(NewBits)))
return getTruncateOrSignExtend(X, Ty);
}
// If the input value is a chrec scev, and we can prove that the value

34
test/Analysis/ScalarEvolution/fold.ll
View File

@ -23,36 +23,40 @@ define i8 @test3(i8 %x) {
ret i8 %C
}
define void @test4(i32 %x) {
define void @test4(i32 %x, i32 %y) {
entry:
%0 = icmp sge i32 %x, 0
br i1 %0, label %loop, label %exit
%Y = and i32 %y, 3
br label %loop
loop:
%A = phi i32 [0, %entry], [%I, %loop]
%rand = icmp sgt i32 %A, 10
%Z = select i1 %rand, i32 %A, i32 10
%B = trunc i32 %Z to i16
%rand1 = icmp sgt i32 %A, %Y
%Z1 = select i1 %rand1, i32 %A, i32 %Y
%rand2 = icmp ugt i32 %A, %Z1
%Z2 = select i1 %rand2, i32 %A, i32 %Z1
; CHECK: %Z2 =
; CHECK-NEXT: --> ([[EXPR:.*]]){{ +}}Exits: 20
%B = trunc i32 %Z2 to i16
%C = sext i16 %B to i30
; CHECK: %C =
; CHECK-NEXT: (trunc i32 (10 smax {0,+,1}<%loop>) to i30)
; CHECK-NEXT: (trunc i32 ([[EXPR]]) to i30)
%D = sext i16 %B to i32
; CHECK: %D =
; CHECK-NEXT: (10 smax {0,+,1}<%loop>)
; CHECK-NEXT: ([[EXPR]])
%E = sext i16 %B to i34
; CHECK: %E =
; CHECK-NEXT: (zext i32 (10 smax {0,+,1}<%loop>) to i34)
; CHECK-NEXT: (zext i32 ([[EXPR]]) to i34)
%F = zext i16 %B to i30
; CHECK: %F =
; CHECK-NEXT: (trunc i32 (10 smax {0,+,1}<%loop>) to i30
; CHECK-NEXT: (trunc i32 ([[EXPR]]) to i30
%G = zext i16 %B to i32
; CHECK: %G =
; CHECK-NEXT: (10 smax {0,+,1}<%loop>)
; CHECK-NEXT: ([[EXPR]])
%H = zext i16 %B to i34
; CHECK: %H =
; CHECK-NEXT: (zext i32 (10 smax {0,+,1}<%loop>) to i34)
; CHECK-NEXT: (zext i32 ([[EXPR]]) to i34)
%I = add i32 %A, 1
%1 = icmp ne i32 %A, 20
br i1 %1, label %loop, label %exit
%0 = icmp ne i32 %A, 20
br i1 %0, label %loop, label %exit
exit:
ret void
}
}