diff options
| -rw-r--r-- | lib/Analysis/ValueTracking.cpp | 10 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/no-negzero.ll | 33 |
2 files changed, 40 insertions, 3 deletions
diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index 9494a2f4c5..baa347a663 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -840,9 +840,13 @@ bool llvm::CannotBeNegativeZero(const Value *V, unsigned Depth) { if (F->isDeclaration()) { // abs(x) != -0.0 if (F->getName() == "abs") return true; - // abs[lf](x) != -0.0 - if (F->getName() == "absf") return true; - if (F->getName() == "absl") return true; + // fabs[lf](x) != -0.0 + if (F->getName() == "fabs") return true; + if (F->getName() == "fabsf") return true; + if (F->getName() == "fabsl") return true; + if (F->getName() == "sqrt" || F->getName() == "sqrtf" || + F->getName() == "sqrtl") + return CannotBeNegativeZero(CI->getOperand(1), Depth+1); } } diff --git a/test/Transforms/InstCombine/no-negzero.ll b/test/Transforms/InstCombine/no-negzero.ll new file mode 100644 index 0000000000..f295130b0e --- /dev/null +++ b/test/Transforms/InstCombine/no-negzero.ll @@ -0,0 +1,33 @@ +; RUN: opt < %s -instcombine -S | FileCheck %s +; ModuleID = '3555a.c' +; sqrt(fabs) cannot be negative zero, so we should eliminate the fadd. +target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128" +target triple = "i386-apple-darwin9.8" + +; CHECK: @mysqrt +; CHECK-NOT: fadd +; CHECK: ret +define double @mysqrt(double %x) nounwind { +entry: + %x_addr = alloca double ; <double*> [#uses=2] + %retval = alloca double, align 8 ; <double*> [#uses=2] + %0 = alloca double, align 8 ; <double*> [#uses=2] + %"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0] + store double %x, double* %x_addr + %1 = load double* %x_addr, align 8 ; <double> [#uses=1] + %2 = call double @fabs(double %1) nounwind readnone ; <double> [#uses=1] + %3 = call double @sqrt(double %2) nounwind readonly ; <double> [#uses=1] + %4 = fadd double %3, 0.000000e+00 ; <double> [#uses=1] + store double %4, double* %0, align 8 + %5 = load double* %0, align 8 ; <double> [#uses=1] + store double %5, double* %retval, align 8 + br label %return + +return: ; preds = %entry + %retval1 = load double* %retval ; <double> [#uses=1] + ret double %retval1 +} + +declare double @fabs(double) + +declare double @sqrt(double) nounwind readonly |