diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index bd57d1192eb94..34e497d9ea3cb 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -3216,13 +3216,16 @@ const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl &Ops, }; } - // Try to fold (C * D /u C) -> D, if C is a power-of-2 and D is a multiple - // of C. + // Try to fold (C1 * D /u C2) -> C1/C2 * D, if C1 and C2 are powers-of-2, + // D is a multiple of C2, and C1 is a multiple of C1. const SCEV *D; - if (match(Ops[1], m_scev_UDiv(m_SCEV(D), m_scev_Specific(LHSC))) && - LHSC->getAPInt().isPowerOf2() && - LHSC->getAPInt().logBase2() <= getMinTrailingZeros(D)) { - return D; + const SCEVConstant *C2; + const APInt &LHSV = LHSC->getAPInt(); + if (LHSV.isPowerOf2() && + match(Ops[1], m_scev_UDiv(m_SCEV(D), m_SCEVConstant(C2))) && + C2->getAPInt().isPowerOf2() && LHSV.uge(C2->getAPInt()) && + LHSV.logBase2() <= getMinTrailingZeros(D)) { + return getMulExpr(getUDivExpr(LHSC, C2), D); } } } diff --git a/llvm/test/Analysis/ScalarEvolution/mul-udiv-folds.ll b/llvm/test/Analysis/ScalarEvolution/mul-udiv-folds.ll index b5d976ba3acda..dfaf0c95bc2f8 100644 --- a/llvm/test/Analysis/ScalarEvolution/mul-udiv-folds.ll +++ b/llvm/test/Analysis/ScalarEvolution/mul-udiv-folds.ll @@ -23,7 +23,7 @@ define void @udiv4_and_udiv2(i1 %c, ptr %A) { ; CHECK-NEXT: %gep.16 = getelementptr i16, ptr %A, i64 %iv ; CHECK-NEXT: --> {((2 * ((zext i32 %start to i64) /u 4)) + %A),+,2}<%loop> U: full-set S: full-set Exits: ((zext i32 %start to i64) + %A) LoopDispositions: { %loop: Computable } ; CHECK-NEXT: %gep.32 = getelementptr i32, ptr %A, i64 %iv -; CHECK-NEXT: --> {((zext i32 %start to i64) + %A),+,4}<%loop> U: full-set S: full-set Exits: ((zext i32 %start to i64) + (4 * ((zext i32 %start to i64) /u 2)) + (-4 * ((zext i32 %start to i64) /u 4)) + %A) LoopDispositions: { %loop: Computable } +; CHECK-NEXT: --> {((zext i32 %start to i64) + %A),+,4}<%loop> U: full-set S: full-set Exits: ((3 * (zext i32 %start to i64)) + (-4 * ((zext i32 %start to i64) /u 4)) + %A) LoopDispositions: { %loop: Computable } ; CHECK-NEXT: %gep.40 = getelementptr <{ i32, i8 }>, ptr %A, i64 %iv ; CHECK-NEXT: --> {((5 * ((zext i32 %start to i64) /u 4)) + %A),+,5}<%loop> U: full-set S: full-set Exits: ((5 * ((zext i32 %start to i64) /u 2)) + %A) LoopDispositions: { %loop: Computable } ; CHECK-NEXT: %gep.48 = getelementptr <{ i32, i16 }>, ptr %A, i64 %iv