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Canonicalization for @llvm.assume

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Adds simple logical canonicalization of assumption intrinsics to instcombine,
currently:
 - invariant(a && b) -> invariant(a); invariant(b)
 - invariant(!(a || b)) -> invariant(!a); invariant(!b)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213977 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel 2014-07-25 21:45:17 +00:00
parent a7f2c540fa
commit 5cb8ab5b5a
2 changed files with 60 additions and 0 deletions
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17
lib/Transforms/InstCombine/InstCombineCalls.cpp
View File

@ -994,6 +994,23 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
return EraseInstFromFunction(CI);
break;
}
case Intrinsic::assume: {
// Canonicalize assume(a && b) -> assume(a); assume(b);
Value *IIOperand = II->getArgOperand(0), *A, *B,
*AssumeIntrinsic = II->getCalledValue();
if (match(IIOperand, m_And(m_Value(A), m_Value(B)))) {
Builder->CreateCall(AssumeIntrinsic, A, II->getName());
Builder->CreateCall(AssumeIntrinsic, B, II->getName());
return EraseInstFromFunction(*II);
}
// assume(!(a || b)) -> assume(!a); assume(!b);
if (match(IIOperand, m_Not(m_Or(m_Value(A), m_Value(B))))) {
Builder->CreateCall(AssumeIntrinsic, Builder->CreateNot(A), II->getName());
Builder->CreateCall(AssumeIntrinsic, Builder->CreateNot(B), II->getName());
return EraseInstFromFunction(*II);
}
break;
}
}
return visitCallSite(II);

43
test/Transforms/InstCombine/assume.ll Normal file
View File

@ -0,0 +1,43 @@
; RUN: opt < %s -instcombine -S | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; Function Attrs: nounwind
declare void @llvm.assume(i1) #1
; Function Attrs: nounwind uwtable
define i32 @can1(i1 %a, i1 %b, i1 %c) {
entry:
%and1 = and i1 %a, %b
%and = and i1 %and1, %c
tail call void @llvm.assume(i1 %and)
; CHECK-LABEL: @can1
; CHECK: call void @llvm.assume(i1 %a)
; CHECK: call void @llvm.assume(i1 %b)
; CHECK: call void @llvm.assume(i1 %c)
; CHECK: ret i32
ret i32 5
}
; Function Attrs: nounwind uwtable
define i32 @can2(i1 %a, i1 %b, i1 %c) {
entry:
%v = or i1 %a, %b
%w = xor i1 %v, 1
tail call void @llvm.assume(i1 %w)
; CHECK-LABEL: @can2
; CHECK: %[[V1:[^ ]+]] = xor i1 %a, true
; CHECK: call void @llvm.assume(i1 %[[V1]])
; CHECK: %[[V2:[^ ]+]] = xor i1 %b, true
; CHECK: call void @llvm.assume(i1 %[[V2]])
; CHECK: ret i32
ret i32 5
}
attributes #0 = { nounwind uwtable }
attributes #1 = { nounwind }