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| author | Benjamin Kramer <benny.kra@googlemail.com> | 2010-12-20 16:18:51 +0000 |
|---|---|---|
| committer | Benjamin Kramer <benny.kra@googlemail.com> | 2010-12-20 16:18:51 +0000 |
| commit | 5337f20c1516296edcea6bc3da6cdc74329142ae (patch) | |
| tree | b344d60db4184b58df32d4eac9a14c511f07601c | |
| parent | 67e0c212c25f478e4c2ac6c8e9c50cce028fb79c (diff) | |
| download | llvm-5337f20c1516296edcea6bc3da6cdc74329142ae.tar.gz llvm-5337f20c1516296edcea6bc3da6cdc74329142ae.tar.bz2 llvm-5337f20c1516296edcea6bc3da6cdc74329142ae.tar.xz | |
Teach InstCombine to merge (icmp ult (X + CA), C1) | (icmp eq X, C2) into (icmp ult (X + CA), C1 + 1) if C2 + CA == C1.
InstCombine creates these so now we compile x == 23 || x == 24 || x == 25 to
%x.off = add i32 %x, -23
%1 = icmp ult i32 %x.off, 3
instead of
%x.off = add i32 %x, -23
%1 = icmp ult i32 %x.off, 2
%cmp3 = icmp eq i32 %x, 25
%ret2 = or i1 %1, %cmp3
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122248 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombineAndOrXor.cpp | 11 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/or.ll | 14 |
2 files changed, 24 insertions, 1 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp index 41734f6ac9..57fe870158 100644 --- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -1450,7 +1450,16 @@ Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS) { return Builder->CreateICmp(LHSCC, NewOr, LHSCst); } } - + + // (icmp ult (X + CA), C1) | (icmp eq X, C2) -> (icmp ult (X + CA), C1 + 1) + // iff C2 + CA == C1. + if (LHSCC == ICmpInst::ICMP_ULT) { + ConstantInt *AddCst; + if (match(Val, m_Add(m_Specific(Val2), m_ConstantInt(AddCst)))) + if (RHSCst->getValue() + AddCst->getValue() == LHSCst->getValue()) + return Builder->CreateICmp(LHSCC, Val, AddOne(LHSCst)); + } + // From here on, we only handle: // (icmp1 A, C1) | (icmp2 A, C2) --> something simpler. if (Val != Val2) return 0; diff --git a/test/Transforms/InstCombine/or.ll b/test/Transforms/InstCombine/or.ll index 500cad2ad6..f82f9faab2 100644 --- a/test/Transforms/InstCombine/or.ll +++ b/test/Transforms/InstCombine/or.ll @@ -376,3 +376,17 @@ define i32 @test35(i32 %a, i32 %b) { ; CHECK-NEXT: or i32 %a, %b ; CHECK-NEXT: or i32 %1, 1135 } + +define i1 @test36(i32 %x) { + %cmp1 = icmp eq i32 %x, 23 + %cmp2 = icmp eq i32 %x, 24 + %ret1 = or i1 %cmp1, %cmp2 + %cmp3 = icmp eq i32 %x, 25 + %ret2 = or i1 %ret1, %cmp3 + ret i1 %ret2 +; CHECK: @test36 +; CHECK-NEXT: %x.off = add i32 %x, -23 +; CHECK-NEXT: icmp ult i32 %x.off, 3 +; CHECK-NEXT: ret i1 +} + |