diff options
| author | Iris Shi <0.0@owo.li> | 2025-06-21 15:30:42 +0800 |
|---|---|---|
| committer | Iris Shi <0.0@owo.li> | 2025-06-21 15:30:42 +0800 |
| commit | 0fc7ec0b45def5d03cb1822bc8672784b5f37fbe (patch) | |
| tree | b5c7280c76d6c215df7dc6fbba750270382a1c9c | |
| parent | 265547e39bd6ade2f3c7cd262dacc5a80a0e4900 (diff) | |
[InstCombine] Fold `exp(exp(x)) / exp(x)` -> `exp(exp(x) - x)`users/el-ev/issue65608
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | 10 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/fdiv-exp.ll | 12 |
2 files changed, 16 insertions, 6 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp index d7310b1c741c..dc79448b247e 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp @@ -2233,6 +2233,16 @@ Instruction *InstCombinerImpl::visitFDiv(BinaryOperator &I) { if (Instruction *Mul = foldFDivPowDivisor(I, Builder)) return Mul; + // exp(exp(X)) / exp(X) -> exp(exp(X) - X) + if (I.hasAllowReassoc() && + match(Op0, m_OneUse(m_Intrinsic<Intrinsic::exp>( + m_Intrinsic<Intrinsic::exp>(m_Value(X))))) && + match(Op1, m_Intrinsic<Intrinsic::exp>(m_Specific(X)))) { + Value *ExpDiff = Builder.CreateFSubFMF(Op1, X, &I); + Value *NewExp = Builder.CreateUnaryIntrinsic(Intrinsic::exp, ExpDiff, &I); + return replaceInstUsesWith(I, NewExp); + } + if (Instruction *Mul = foldFDivSqrtDivisor(I, Builder)) return Mul; diff --git a/llvm/test/Transforms/InstCombine/fdiv-exp.ll b/llvm/test/Transforms/InstCombine/fdiv-exp.ll index a355c3bc6666..32f231e6e93b 100644 --- a/llvm/test/Transforms/InstCombine/fdiv-exp.ll +++ b/llvm/test/Transforms/InstCombine/fdiv-exp.ll @@ -6,8 +6,8 @@ define half @fdiv_exp_half(half %x) { ; CHECK-SAME: half [[X:%.*]]) { ; CHECK-NEXT: [[ENTRY:.*:]] ; CHECK-NEXT: [[EXP_X:%.*]] = call fast half @llvm.exp.f16(half [[X]]) -; CHECK-NEXT: [[EXP_EXP_X:%.*]] = call fast half @llvm.exp.f16(half [[EXP_X]]) -; CHECK-NEXT: [[DIV:%.*]] = fdiv fast half [[EXP_EXP_X]], [[EXP_X]] +; CHECK-NEXT: [[TMP0:%.*]] = fsub fast half [[EXP_X]], [[X]] +; CHECK-NEXT: [[DIV:%.*]] = call fast half @llvm.exp.f16(half [[TMP0]]) ; CHECK-NEXT: ret half [[DIV]] ; entry: @@ -22,8 +22,8 @@ define float @fdiv_exp_float(float %x) { ; CHECK-SAME: float [[X:%.*]]) { ; CHECK-NEXT: [[ENTRY:.*:]] ; CHECK-NEXT: [[EXP_X:%.*]] = call fast float @llvm.exp.f32(float [[X]]) -; CHECK-NEXT: [[EXP_EXP_X:%.*]] = call fast float @llvm.exp.f32(float [[EXP_X]]) -; CHECK-NEXT: [[DIV:%.*]] = fdiv fast float [[EXP_EXP_X]], [[EXP_X]] +; CHECK-NEXT: [[TMP0:%.*]] = fsub fast float [[EXP_X]], [[X]] +; CHECK-NEXT: [[DIV:%.*]] = call fast float @llvm.exp.f32(float [[TMP0]]) ; CHECK-NEXT: ret float [[DIV]] ; entry: @@ -38,8 +38,8 @@ define double @fdiv_exp_double(double %x) { ; CHECK-SAME: double [[X:%.*]]) { ; CHECK-NEXT: [[ENTRY:.*:]] ; CHECK-NEXT: [[EXP_X:%.*]] = call fast double @llvm.exp.f64(double [[X]]) -; CHECK-NEXT: [[EXP_EXP_X:%.*]] = call fast double @llvm.exp.f64(double [[EXP_X]]) -; CHECK-NEXT: [[DIV:%.*]] = fdiv fast double [[EXP_EXP_X]], [[EXP_X]] +; CHECK-NEXT: [[TMP0:%.*]] = fsub fast double [[EXP_X]], [[X]] +; CHECK-NEXT: [[DIV:%.*]] = call fast double @llvm.exp.f64(double [[TMP0]]) ; CHECK-NEXT: ret double [[DIV]] ; entry: |