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implement the transform requested in PR5284

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92398 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2010-01-01 18:34:40 +00:00
parent bfdfea86a1
commit e33d413152
2 changed files with 37 additions and 7 deletions
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13
lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -10139,6 +10139,19 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(II->getOperand(1)))
if (Operand->getIntrinsicID() == Intrinsic::bswap)
return ReplaceInstUsesWith(CI, Operand->getOperand(1));
// bswap(trunc(bswap(x))) -> trunc(lshr(x, c))
if (TruncInst *TI = dyn_cast<TruncInst>(II->getOperand(1))) {
if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(TI->getOperand(0)))
if (Operand->getIntrinsicID() == Intrinsic::bswap) {
unsigned C = Operand->getType()->getPrimitiveSizeInBits() -
TI->getType()->getPrimitiveSizeInBits();
Value *CV = ConstantInt::get(Operand->getType(), C);
Value *V = Builder->CreateLShr(Operand->getOperand(1), CV);
return new TruncInst(V, TI->getType());
}
}
break;
case Intrinsic::powi:
if (ConstantInt *Power = dyn_cast<ConstantInt>(II->getOperand(2))) {

31
test/Transforms/InstCombine/bswap-fold.ll
View File

@ -1,23 +1,22 @@
; RUN: opt < %s -instcombine -S | grep ret | count 6
; RUN: opt < %s -instcombine -S | not grep call.*bswap
define i1 @test1(i16 %tmp2) {
%tmp10 = call i16 @llvm.bswap.i16( i16 %tmp2 ) ; <i16> [#uses=1]
%tmp = icmp eq i16 %tmp10, 1 ; <i1> [#uses=1]
%tmp10 = call i16 @llvm.bswap.i16( i16 %tmp2 )
%tmp = icmp eq i16 %tmp10, 1
ret i1 %tmp
}
define i1 @test2(i32 %tmp) {
%tmp34 = tail call i32 @llvm.bswap.i32( i32 %tmp ) ; <i32> [#uses=1]
%tmp.upgrd.1 = icmp eq i32 %tmp34, 1 ; <i1> [#uses=1]
%tmp34 = tail call i32 @llvm.bswap.i32( i32 %tmp )
%tmp.upgrd.1 = icmp eq i32 %tmp34, 1
ret i1 %tmp.upgrd.1
}
declare i32 @llvm.bswap.i32(i32)
define i1 @test3(i64 %tmp) {
%tmp34 = tail call i64 @llvm.bswap.i64( i64 %tmp ) ; <i64> [#uses=1]
%tmp.upgrd.2 = icmp eq i64 %tmp34, 1 ; <i1> [#uses=1]
%tmp34 = tail call i64 @llvm.bswap.i64( i64 %tmp )
%tmp.upgrd.2 = icmp eq i64 %tmp34, 1
ret i1 %tmp.upgrd.2
}
@ -50,3 +49,21 @@ entry:
ret i32 %tmp4
}
; PR5284
declare i64 @llvm.bswap.i64(i64)
declare i32 @llvm.bswap.i32(i32)
declare i16 @llvm.bswap.i16(i16)
define i16 @test7(i32 %A) {
%B = tail call i32 @llvm.bswap.i32(i32 %A) nounwind
%C = trunc i32 %B to i16
%D = tail call i16 @llvm.bswap.i16(i16 %C) nounwind
ret i16 %D
}
define i16 @test8(i64 %A) {
%B = tail call i64 @llvm.bswap.i64(i64 %A) nounwind
%C = trunc i64 %B to i16
%D = tail call i16 @llvm.bswap.i16(i16 %C) nounwind
ret i16 %D
}