diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp --- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp @@ -6225,6 +6225,26 @@ } } + // If none of the above worked, but there are no NaNs, then expand to + // a compare/select sequence. This is required for correctness since + // InstCombine might have canonicalized a fcmp+select sequence to a + // FMINNUM/FMAXNUM node. If we were to fall through to the default + // expansion to libcall, we might introduce a link-time dependency + // on libm into a file that originally did not have one. + if (Node->getFlags().hasNoNaNs()) { + ISD::CondCode Pred = + Node->getOpcode() == ISD::FMINNUM ? ISD::SETLT : ISD::SETGT; + SDValue Op1 = Node->getOperand(0); + SDValue Op2 = Node->getOperand(1); + SDValue SelCC = DAG.getSelectCC(dl, Op1, Op2, Op1, Op2, Pred); + // Copy FMF flags, but always set the no-signed-zeros flag + // as this is implied by the FMINNUM/FMAXNUM semantics. + SDNodeFlags Flags = Node->getFlags(); + Flags.setNoSignedZeros(true); + SelCC->setFlags(Flags); + return SelCC; + } + return SDValue(); } diff --git a/llvm/test/CodeGen/SystemZ/fp-libcall.ll b/llvm/test/CodeGen/SystemZ/fp-libcall.ll --- a/llvm/test/CodeGen/SystemZ/fp-libcall.ll +++ b/llvm/test/CodeGen/SystemZ/fp-libcall.ll @@ -233,6 +233,68 @@ ret fp128 %tmp } +; Verify that "nnan" minnum/maxnum calls are transformed to +; compare+select sequences instead of libcalls. +define float @f34(float %x, float %y) { +; CHECK-LABEL: f34: +; CHECK: cebr %f0, %f2 +; CHECK: blr %r14 +; CHECK: ler %f0, %f2 +; CHECK: br %r14 + %tmp = call nnan float @llvm.minnum.f32(float %x, float %y) + ret float %tmp +} + +define double @f35(double %x, double %y) { +; CHECK-LABEL: f35: +; CHECK: cdbr %f0, %f2 +; CHECK: blr %r14 +; CHECK: ldr %f0, %f2 +; CHECK: br %r14 + %tmp = call nnan double @llvm.minnum.f64(double %x, double %y) + ret double %tmp +} + +define fp128 @f36(fp128 %x, fp128 %y) { +; CHECK-LABEL: f36: +; CHECK: cxbr +; CHECK: jl +; CHECK: lxr +; CHECK: br %r14 + %tmp = call nnan fp128 @llvm.minnum.f128(fp128 %x, fp128 %y) + ret fp128 %tmp +} + +define float @f37(float %x, float %y) { +; CHECK-LABEL: f37: +; CHECK: cebr %f0, %f2 +; CHECK: bhr %r14 +; CHECK: ler %f0, %f2 +; CHECK: br %r14 + %tmp = call nnan float @llvm.maxnum.f32(float %x, float %y) + ret float %tmp +} + +define double @f38(double %x, double %y) { +; CHECK-LABEL: f38: +; CHECK: cdbr %f0, %f2 +; CHECK: bhr %r14 +; CHECK: ldr %f0, %f2 +; CHECK: br %r14 + %tmp = call nnan double @llvm.maxnum.f64(double %x, double %y) + ret double %tmp +} + +define fp128 @f39(fp128 %x, fp128 %y) { +; CHECK-LABEL: f39: +; CHECK: cxbr +; CHECK: jh +; CHECK: lxr +; CHECK: br %r14 + %tmp = call nnan fp128 @llvm.maxnum.f128(fp128 %x, fp128 %y) + ret fp128 %tmp +} + declare float @llvm.powi.f32(float, i32) declare double @llvm.powi.f64(double, i32) declare fp128 @llvm.powi.f128(fp128, i32)