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Handle ands with ~0 correctly too. This fixes PR4052. 

llvm-svn: 70176
This commit is contained in:
Dan Gohman 2009-04-27 01:41:10 +00:00
parent 6019e07b3b
commit 05c1d372b7
2 changed files with 105 additions and 0 deletions
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2
llvm/lib/Analysis/ScalarEvolution.cpp
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@ -1756,6 +1756,8 @@ SCEVHandle ScalarEvolution::createSCEV(Value *V) {
if (ConstantInt *CI = dyn_cast<ConstantInt>(U->getOperand(1))) {
if (CI->isNullValue())
return getSCEV(U->getOperand(1));
if (CI->isAllOnesValue())
return getSCEV(U->getOperand(0));
const APInt &A = CI->getValue();
unsigned Ones = A.countTrailingOnes();
if (APIntOps::isMask(Ones, A))

103
llvm/test/Transforms/IndVarSimplify/avoid-i0.ll
View File

@ -1,4 +1,5 @@
; RUN: llvm-as < %s | opt -indvars
; PR4052
; PR4054
; Don't treat an and with 0 as a mask (trunc+zext).
@ -21,3 +22,105 @@ bb6: ; preds = %bb4
%0 = and i8 0, 0 ; <i8> [#uses=1]
br label %bb
}
@x = common global i32 0 ; <i32*> [#uses=1]
define signext i8 @safe_sub_func_int32_t_s_s(i32 %_si1, i8 signext %_si2) nounwind {
entry:
%_si1_addr = alloca i32 ; <i32*> [#uses=3]
%_si2_addr = alloca i8 ; <i8*> [#uses=3]
%retval = alloca i32 ; <i32*> [#uses=2]
%0 = alloca i32 ; <i32*> [#uses=2]
%"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0]
store i32 %_si1, i32* %_si1_addr
store i8 %_si2, i8* %_si2_addr
%1 = load i8* %_si2_addr, align 1 ; <i8> [#uses=1]
%2 = sext i8 %1 to i32 ; <i32> [#uses=1]
%3 = load i32* %_si1_addr, align 4 ; <i32> [#uses=1]
%4 = xor i32 %2, %3 ; <i32> [#uses=1]
%5 = load i8* %_si2_addr, align 1 ; <i8> [#uses=1]
%6 = sext i8 %5 to i32 ; <i32> [#uses=1]
%7 = sub i32 7, %6 ; <i32> [#uses=1]
%8 = load i32* %_si1_addr, align 4 ; <i32> [#uses=1]
%9 = shl i32 %8, %7 ; <i32> [#uses=1]
%10 = and i32 %4, %9 ; <i32> [#uses=1]
%11 = icmp slt i32 %10, 0 ; <i1> [#uses=1]
%12 = zext i1 %11 to i32 ; <i32> [#uses=1]
store i32 %12, i32* %0, align 4
%13 = load i32* %0, align 4 ; <i32> [#uses=1]
store i32 %13, i32* %retval, align 4
br label %return
return: ; preds = %entry
%retval1 = load i32* %retval ; <i32> [#uses=1]
%retval12 = trunc i32 %retval1 to i8 ; <i8> [#uses=1]
ret i8 %retval12
}
define i32 @safe_sub_func_uint64_t_u_u(i32 %_ui1, i32 %_ui2) nounwind {
entry:
%_ui1_addr = alloca i32 ; <i32*> [#uses=2]
%_ui2_addr = alloca i32 ; <i32*> [#uses=1]
%retval = alloca i32 ; <i32*> [#uses=2]
%0 = alloca i32 ; <i32*> [#uses=2]
%"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0]
store i32 %_ui1, i32* %_ui1_addr
store i32 %_ui2, i32* %_ui2_addr
%1 = load i32* %_ui1_addr, align 4 ; <i32> [#uses=1]
%2 = sub i32 %1, 1 ; <i32> [#uses=1]
store i32 %2, i32* %0, align 4
%3 = load i32* %0, align 4 ; <i32> [#uses=1]
store i32 %3, i32* %retval, align 4
br label %return
return: ; preds = %entry
%retval1 = load i32* %retval ; <i32> [#uses=1]
ret i32 %retval1
}
define void @int87(i8 signext %p_48, i8 signext %p_49) nounwind {
entry:
%p_48_addr = alloca i8 ; <i8*> [#uses=1]
%p_49_addr = alloca i8 ; <i8*> [#uses=1]
%l_52 = alloca i32 ; <i32*> [#uses=7]
%vol.0 = alloca i32 ; <i32*> [#uses=1]
%"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0]
store i8 %p_48, i8* %p_48_addr
store i8 %p_49, i8* %p_49_addr
br label %bb4
bb: ; preds = %bb4
%0 = volatile load i32* @x, align 4 ; <i32> [#uses=1]
store i32 %0, i32* %vol.0, align 4
store i32 0, i32* %l_52, align 4
br label %bb2
bb1: ; preds = %bb2
%1 = load i32* %l_52, align 4 ; <i32> [#uses=1]
%2 = call i32 @safe_sub_func_uint64_t_u_u(i32 %1, i32 1) nounwind ; <i32> [#uses=1]
store i32 %2, i32* %l_52, align 4
br label %bb2
bb2: ; preds = %bb1, %bb
%3 = load i32* %l_52, align 4 ; <i32> [#uses=1]
%4 = icmp eq i32 %3, 0 ; <i1> [#uses=1]
br i1 %4, label %bb1, label %bb3
bb3: ; preds = %bb2
%5 = load i32* %l_52, align 4 ; <i32> [#uses=1]
%6 = call signext i8 @safe_sub_func_int32_t_s_s(i32 %5, i8 signext 1) nounwind ; <i8> [#uses=1]
%7 = sext i8 %6 to i32 ; <i32> [#uses=1]
store i32 %7, i32* %l_52, align 4
br label %bb4
bb4: ; preds = %bb3, %entry
%8 = load i32* %l_52, align 4 ; <i32> [#uses=1]
%9 = icmp ne i32 %8, 0 ; <i1> [#uses=1]
br i1 %9, label %bb, label %bb5
bb5: ; preds = %bb4
br label %return
return: ; preds = %bb5
ret void
}