Assume ieee behavior without denormal-fp-math attribute

[cameron.mcinally]

LGTM

[cameron.mcinally]

Ah, I didn't realize there were test differences from this change. It should probably be combined with D69988...

[arsenm]

Include x86 test updates

[cameron.mcinally]

Attn: @craig.topper @eli.friedman. The FMF behavior looks like it will take a performance hit with the switch to default IEEE conformance. Is this something that needs to be publicized on llvm-dev before merging? Users who don't care will want to add an explicit denormal-fp-math attribute to their code.

Nit: the IR tests may be overly brittle -- checking for specific registers. It might be good to use update_test_checks.py so that we get the regex'd register expressions.

[spatel]

In D69989#1753683, @cameron.mcinally wrote:

Attn: @craig.topper @eli.friedman. The FMF behavior looks like it will take a performance hit with the switch to default IEEE conformance. Is this something that needs to be publicized on llvm-dev before merging? Users who don't care will want to add an explicit denormal-fp-math attribute to their code.

I think this patch is dependent on D69979 (set the denorm attributes based on other clang behavior). We need a test-suite end-to-end test or at least have clang tests reference the expected codegen tests, so we know that handshake between front-end and codegen is working as expected.

Nit: the IR tests may be overly brittle -- checking for specific registers. It might be good to use update_test_checks.py so that we get the regex'd register expressions.

Agree - if possible, regenerate/add tests as NFC changes before this patch.

[arsenm]

Rebase

[spatel]

llvm/test/CodeGen/X86/sqrt-fastmath-tune.ll

101 ↗

(On Diff #244283)

Does the "preseve" typo affect anything?

[arsenm]

llvm/test/CodeGen/X86/sqrt-fastmath-tune.ll

101 ↗

(On Diff #244283)

These aren't hitting the expansion, so I guess it doesn't. I assume this has something to do with not using reciprocal-estimates?

[spatel]

llvm/test/CodeGen/X86/sqrt-fastmath-tune.ll

101 ↗

(On Diff #244283)

Yes, this file isn't well-specified about what it's trying to test for. I updated it here:
rG6071fc57a45f

That should remove it from this patch?

Independent of that - should we have an assert or warning that would catch typos in the attribute string?

[arsenm]

llvm/test/CodeGen/X86/sqrt-fastmath-tune.ll

101 ↗

(On Diff #244283)

I remember implementing a verifier check for this before ,but I can't seem to find the patch

[spatel]

llvm/test/CodeGen/X86/sqrt-fastmath-tune.ll

101 ↗

(On Diff #244283)

It would be good to revive that patch for safety. But this patch doesn't need to be gated by that improvement (IIUC, these diffs disappear if you rebase?).

[arsenm]

Rebase to eliminate test diff

[spatel]

clang/lib/CodeGen/CGCall.cpp

1754

I haven't followed the FP32 patches as closely as others, so I might have missed the reasoning here.

As-is, we may need to explicitly say that FP32 is IEEE while everything is else is not (although I assume that would be a strange config).

Do we have a test for that?
Is that better than making the FP32 attribute behave like the other FP attribute (assume IEEE unless otherwise specified)?

clang/test/Driver/denormal-fp-math.c

11

Remove 'TODO', but restore 'ieee'?

[arsenm]

clang/lib/CodeGen/CGCall.cpp

1754

denormal-fp-math sets the mode for all types. denormal-fp-math-f32 overrides it in the case of f32. It's still possible to configure a function to assume flushing for non-f32, and ieee for f32. We do have backend tests for the strange IEEE f32, non-IEEE other case in the backend but I'm not sure for the frontend flag handling

[arsenm]

clang/lib/CodeGen/CGCall.cpp

1754

Now that I think of it, I don't think it's possible to specify the backwards case since I only allowed -denormal-fp-math-f32 as a cc1 flag. The only user facing way to set it is through -cl-denorms-are-zero, which depends on the target handling, which doesn't want to flush non-f32

[arsenm]

Fix comment

[spatel]

llvm/test/CodeGen/X86/sqrt-fastmath-mir.ll

115–117

Double-check my understanding: we have the "ieee,ieee" attribute here, but we would never expect to see that in practice?

[arsenm]

llvm/test/CodeGen/X86/sqrt-fastmath-mir.ll

115–117

Yes, ieee,ieee is the default, but explicitly setting it is also valid. In the AMDGPU specific patches, I switched the default based on calling convention for graphics shaders (but I like this less over time, and may remove this detail)

[spatel]

LGTM

[arsenm]

a4e71f01c08fbaeaccfe3e11cc08790432cc7e45

[arsenm]

I can't seem to close this? @cameron.mcinally?

clang/lib/CodeGen/CGCall.cpp

if (AttrOnCallSite) {
     FuncAttrs.addAttribute("frame-pointer", FpKind);
 
     FuncAttrs.addAttribute("less-precise-fpmad",
                            llvm::toStringRef(CodeGenOpts.LessPreciseFPMAD));
 
     if (CodeGenOpts.NullPointerIsValid)
       FuncAttrs.addAttribute("null-pointer-is-valid", "true");
 
-    // TODO: Omit attribute when the default is IEEE.
-    if (CodeGenOpts.FPDenormalMode.isValid())
+    if (CodeGenOpts.FPDenormalMode != llvm::DenormalMode::getIEEE())
       FuncAttrs.addAttribute("denormal-fp-math",
                              CodeGenOpts.FPDenormalMode.str());
-    if (CodeGenOpts.FP32DenormalMode.isValid()) {
+    if (CodeGenOpts.FP32DenormalMode != CodeGenOpts.FPDenormalMode) {
       FuncAttrs.addAttribute(
           "denormal-fp-math-f32",
           CodeGenOpts.FP32DenormalMode.str());
     }
 
     FuncAttrs.addAttribute("no-trapping-math",
                            llvm::toStringRef(CodeGenOpts.NoTrappingMath));
 

clang/lib/Driver/ToolChains/Clang.cpp

static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
 
   if (TrappingMath) {
     // FP Exception Behavior is also set to strict
     assert(FPExceptionBehavior.equals("strict"));
     CmdArgs.push_back("-ftrapping-math");
   } else if (TrappingMathPresent)
     CmdArgs.push_back("-fno-trapping-math");
 
-  // TODO: Omit flag for the default IEEE instead
-  if (DenormalFPMath.isValid()) {
+  // The default is IEEE.
+  if (DenormalFPMath != llvm::DenormalMode::getIEEE()) {
     llvm::SmallString<64> DenormFlag;
     llvm::raw_svector_ostream ArgStr(DenormFlag);
     ArgStr << "-fdenormal-fp-math=" << DenormalFPMath;
     CmdArgs.push_back(Args.MakeArgString(ArgStr.str()));
   }
 
   // Add f32 specific denormal mode flag if it's different.
   if (DenormalFP32Math != DenormalFPMath) {

clang/test/CodeGen/denormalfpmode.c

 // RUN: %clang_cc1 -S -fdenormal-fp-math=ieee %s -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-IEEE
 // RUN: %clang_cc1 -S -fdenormal-fp-math=preserve-sign %s -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-PS
 // RUN: %clang_cc1 -S -fdenormal-fp-math=positive-zero %s -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-PZ
 
 // CHECK-LABEL: main
-// CHECK-IEEE: attributes #0 = {{.*}}"denormal-fp-math"="ieee,ieee"{{.*}}
+
+// The ieee,ieee is the default, so omit the attribute
+// CHECK-IEEE-NOT:"denormal-fp-math"
 // CHECK-PS: attributes #0 = {{.*}}"denormal-fp-math"="preserve-sign,preserve-sign"{{.*}}
 // CHECK-PZ: attributes #0 = {{.*}}"denormal-fp-math"="positive-zero,positive-zero"{{.*}}
 
 int main() {
   return 0;
 }

clang/test/CodeGenCUDA/flush-denormals.cu

 // For AMDGCN target with fast FMAF (e.g. gfx900), it has +fp32-denormals
 // by default and -fp32-denormals when there is option
 // -fcuda-flush-denormals-to-zero.
 
 // CHECK-LABEL: define void @foo() #0
 extern "C" __device__ void foo() {}
 
 // FTZ: attributes #0 = {{.*}} "denormal-fp-math-f32"="preserve-sign,preserve-sign"
-// NOFTZ: attributes #0 = {{.*}} "denormal-fp-math-f32"="ieee,ieee"
+// NOFTZ-NOT: "denormal-fp-math-f32"
 
 // AMDNOFTZ: attributes #0 = {{.*}}+fp32-denormals{{.*}}+fp64-fp16-denormals
 // AMDFTZ: attributes #0 = {{.*}}+fp64-fp16-denormals{{.*}}-fp32-denormals
 
 // FTZ:!llvm.module.flags = !{{{.*}}[[MODFLAG:![0-9]+]]}
 // FTZ:[[MODFLAG]] = !{i32 4, !"nvvm-reflect-ftz", i32 1}
 
 // NOFTZ:!llvm.module.flags = !{{{.*}}[[MODFLAG:![0-9]+]]}
 // NOFTZ:[[MODFLAG]] = !{i32 4, !"nvvm-reflect-ftz", i32 0}

clang/test/CodeGenCUDA/propagate-metadata.cu

 // NOFAST-NOT: "unsafe-fp-math"="true"
 
 // Check the attribute list for lib_fn.
 // CHECK: attributes [[fattr]] = {
 
 // CHECK-SAME: convergent
 // CHECK-NOT: norecurse
 
-// FTZ-SAME: "denormal-fp-math"="ieee,ieee"
-// NOFTZ-SAME: "denormal-fp-math"="ieee,ieee"
+// FTZ-NOT: "denormal-fp-math"
+// NOFTZ-NOT: "denormal-fp-math"
 
 // FTZ-SAME: "denormal-fp-math-f32"="preserve-sign,preserve-sign"
-// NOFTZ-SAME: "denormal-fp-math-f32"="ieee,ieee"
+// NOFTZ-NOT: "denormal-fp-math-f32"
 
 // CHECK-SAME: "no-trapping-math"="true"
 
 // FAST-SAME: "unsafe-fp-math"="true"
 // NOFAST-NOT: "unsafe-fp-math"="true"

clang/test/Driver/denormal-fp-math.c

 // RUN: %clang -### -target arm-unknown-linux-gnu -c %s -fdenormal-fp-math=ieee -v 2>&1 | FileCheck -check-prefix=CHECK-IEEE %s
 // RUN: %clang -### -target arm-unknown-linux-gnu -c %s -fdenormal-fp-math=preserve-sign -v 2>&1 | FileCheck -check-prefix=CHECK-PS %s
 // RUN: %clang -### -target arm-unknown-linux-gnu -c %s -fdenormal-fp-math=positive-zero -v 2>&1 | FileCheck -check-prefix=CHECK-PZ %s
 // RUN: %clang -### -target arm-unknown-linux-gnu -c %s -fdenormal-fp-math=ieee -fno-fast-math -v 2>&1 | FileCheck -check-prefix=CHECK-NO-UNSAFE %s
 // RUN: %clang -### -target arm-unknown-linux-gnu -c %s -fdenormal-fp-math=ieee -fno-unsafe-math-optimizations -v 2>&1 | FileCheck -check-prefix=CHECK-NO-UNSAFE %s
 // RUN: not %clang -target arm-unknown-linux-gnu -c %s -fdenormal-fp-math=foo -v 2>&1 | FileCheck -check-prefix=CHECK-INVALID0 %s
 // RUN: not %clang -target arm-unknown-linux-gnu -c %s -fdenormal-fp-math=ieee,foo -v 2>&1 | FileCheck -check-prefix=CHECK-INVALID1 %s
 // RUN: not %clang -target arm-unknown-linux-gnu -c %s -fdenormal-fp-math=foo,ieee -v 2>&1 | FileCheck -check-prefix=CHECK-INVALID2 %s
 // RUN: not %clang -target arm-unknown-linux-gnu -c %s -fdenormal-fp-math=foo,foo -v 2>&1 | FileCheck -check-prefix=CHECK-INVALID3 %s
 
-// TODO: ieee is the implied default, and the flag is not passed.
-// CHECK-IEEE: "-fdenormal-fp-math=ieee,ieee"
+// TODO: is the implied default, and the flag is not passed.
+// CHECK-IEEE-NOT: -fdenormal-fp-math=
 // CHECK-PS: "-fdenormal-fp-math=preserve-sign,preserve-sign"
 // CHECK-PZ: "-fdenormal-fp-math=positive-zero,positive-zero"
 // CHECK-NO-UNSAFE-NOT: "-fdenormal-fp-math=ieee"
 // CHECK-INVALID0: error: invalid value 'foo' in '-fdenormal-fp-math=foo'
 // CHECK-INVALID1: error: invalid value 'ieee,foo' in '-fdenormal-fp-math=ieee,foo'
 // CHECK-INVALID2: error: invalid value 'foo,ieee' in '-fdenormal-fp-math=foo,ieee'
 // CHECK-INVALID3: error: invalid value 'foo,foo' in '-fdenormal-fp-math=foo,foo'

llvm/lib/CodeGen/MachineFunction.cpp

if (&FPType == &APFloat::IEEEsingle()) {
 
     // If the f32 variant of the attribute isn't specified, try to use the
     // generic one.
   }
 
   // TODO: Should probably avoid the connection to the IR and store directly
   // in the MachineFunction.
   Attribute Attr = F.getFnAttribute("denormal-fp-math");
-
-  // FIXME: This should assume IEEE behavior on an unspecified
-  // attribute. However, the one current user incorrectly assumes a non-IEEE
-  // target by default.
-  StringRef Val = Attr.getValueAsString();
-  if (Val.empty())
-    return DenormalMode::getInvalid();
-
-  return parseDenormalFPAttribute(Val);
+  return parseDenormalFPAttribute(Attr.getValueAsString());
 }
 
 /// Should we be emitting segmented stack stuff for the function
 bool MachineFunction::shouldSplitStack() const {
   return getFunction().hasFnAttribute("split-stack");
 }
 
 LLVM_NODISCARD unsigned

llvm/test/CodeGen/X86/pow.ll

 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc < %s -mtriple=x86_64-- | FileCheck %s
 
 declare float @llvm.pow.f32(float, float)
 declare <4 x float> @llvm.pow.v4f32(<4 x float>, <4 x float>)
 
 declare double @llvm.pow.f64(double, double)
 declare <2 x double> @llvm.pow.v2f64(<2 x double>, <2 x double>)
 
 declare x86_fp80 @llvm.pow.f80(x86_fp80, x86_fp80)
 
-define float @pow_f32_one_fourth_fmf(float %x) nounwind {
-; CHECK-LABEL: pow_f32_one_fourth_fmf:
+define float @pow_f32_one_fourth_fmf_ieee(float %x) nounwind {
+; CHECK-LABEL: pow_f32_one_fourth_fmf_ieee:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    rsqrtss %xmm0, %xmm1
+; CHECK-NEXT:    movaps %xmm0, %xmm3
+; CHECK-NEXT:    mulss %xmm1, %xmm3
+; CHECK-NEXT:    movss {{.*#+}} xmm2 = mem[0],zero,zero,zero
+; CHECK-NEXT:    movaps %xmm3, %xmm4
+; CHECK-NEXT:    mulss %xmm2, %xmm4
+; CHECK-NEXT:    mulss %xmm1, %xmm3
+; CHECK-NEXT:    movss {{.*#+}} xmm5 = mem[0],zero,zero,zero
+; CHECK-NEXT:    addss %xmm5, %xmm3
+; CHECK-NEXT:    mulss %xmm4, %xmm3
+; CHECK-NEXT:    movaps {{.*#+}} xmm1 = [NaN,NaN,NaN,NaN]
+; CHECK-NEXT:    andps %xmm1, %xmm0
+; CHECK-NEXT:    movss {{.*#+}} xmm4 = mem[0],zero,zero,zero
+; CHECK-NEXT:    cmpltss %xmm4, %xmm0
+; CHECK-NEXT:    andnps %xmm3, %xmm0
+; CHECK-NEXT:    xorps %xmm3, %xmm3
+; CHECK-NEXT:    rsqrtss %xmm0, %xmm3
+; CHECK-NEXT:    andps %xmm0, %xmm1
+; CHECK-NEXT:    mulss %xmm3, %xmm0
+; CHECK-NEXT:    mulss %xmm0, %xmm2
+; CHECK-NEXT:    mulss %xmm3, %xmm0
+; CHECK-NEXT:    addss %xmm5, %xmm0
+; CHECK-NEXT:    mulss %xmm2, %xmm0
+; CHECK-NEXT:    cmpltss %xmm4, %xmm1
+; CHECK-NEXT:    andnps %xmm0, %xmm1
+; CHECK-NEXT:    movaps %xmm1, %xmm0
+; CHECK-NEXT:    retq
+  %r = call nsz ninf afn float @llvm.pow.f32(float %x, float 2.5e-01)
+  ret float %r
+}
+
+define float @pow_f32_one_fourth_fmf_daz(float %x) #0 {
+; CHECK-LABEL: pow_f32_one_fourth_fmf_daz:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    rsqrtss %xmm0, %xmm1
 ; CHECK-NEXT:    movaps %xmm0, %xmm2
 ; CHECK-NEXT:    mulss %xmm1, %xmm2
 ; CHECK-NEXT:    movss {{.*#+}} xmm3 = mem[0],zero,zero,zero
 ; CHECK-NEXT:    movaps %xmm2, %xmm4
 ; CHECK-NEXT:    mulss %xmm3, %xmm4
 ; CHECK-NEXT:    mulss %xmm1, %xmm2

 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    rsqrtps %xmm0, %xmm1
 ; CHECK-NEXT:    movaps %xmm0, %xmm2
 ; CHECK-NEXT:    mulps %xmm1, %xmm2
 ; CHECK-NEXT:    movaps {{.*#+}} xmm3 = [-5.0E-1,-5.0E-1,-5.0E-1,-5.0E-1]
 ; CHECK-NEXT:    movaps %xmm2, %xmm4
 ; CHECK-NEXT:    mulps %xmm3, %xmm4
 ; CHECK-NEXT:    mulps %xmm1, %xmm2
-; CHECK-NEXT:    movaps {{.*#+}} xmm1 = [-3.0E+0,-3.0E+0,-3.0E+0,-3.0E+0]
-; CHECK-NEXT:    addps %xmm1, %xmm2
+; CHECK-NEXT:    movaps {{.*#+}} xmm5 = [-3.0E+0,-3.0E+0,-3.0E+0,-3.0E+0]
+; CHECK-NEXT:    addps %xmm5, %xmm2
 ; CHECK-NEXT:    mulps %xmm4, %xmm2
-; CHECK-NEXT:    xorps %xmm4, %xmm4
-; CHECK-NEXT:    cmpneqps %xmm4, %xmm0
-; CHECK-NEXT:    andps %xmm2, %xmm0
-; CHECK-NEXT:    rsqrtps %xmm0, %xmm2
-; CHECK-NEXT:    movaps %xmm0, %xmm5
-; CHECK-NEXT:    mulps %xmm2, %xmm5
-; CHECK-NEXT:    mulps %xmm5, %xmm3
-; CHECK-NEXT:    mulps %xmm2, %xmm5
-; CHECK-NEXT:    addps %xmm1, %xmm5
-; CHECK-NEXT:    mulps %xmm3, %xmm5
-; CHECK-NEXT:    cmpneqps %xmm4, %xmm0
-; CHECK-NEXT:    andps %xmm5, %xmm0
+; CHECK-NEXT:    movaps {{.*#+}} xmm4 = [NaN,NaN,NaN,NaN]
+; CHECK-NEXT:    andps %xmm4, %xmm0
+; CHECK-NEXT:    movaps {{.*#+}} xmm1 = [1.17549435E-38,1.17549435E-38,1.17549435E-38,1.17549435E-38]
+; CHECK-NEXT:    movaps %xmm1, %xmm6
+; CHECK-NEXT:    cmpleps %xmm0, %xmm6
+; CHECK-NEXT:    andps %xmm2, %xmm6
+; CHECK-NEXT:    rsqrtps %xmm6, %xmm0
+; CHECK-NEXT:    movaps %xmm6, %xmm2
+; CHECK-NEXT:    mulps %xmm0, %xmm2
+; CHECK-NEXT:    mulps %xmm2, %xmm3
+; CHECK-NEXT:    mulps %xmm0, %xmm2
+; CHECK-NEXT:    addps %xmm5, %xmm2
+; CHECK-NEXT:    mulps %xmm3, %xmm2
+; CHECK-NEXT:    andps %xmm4, %xmm6
+; CHECK-NEXT:    cmpleps %xmm6, %xmm1
+; CHECK-NEXT:    andps %xmm2, %xmm1
+; CHECK-NEXT:    movaps %xmm1, %xmm0
 ; CHECK-NEXT:    retq
   %r = call fast <4 x float> @llvm.pow.v4f32(<4 x float> %x, <4 x float> <float 2.5e-1, float 2.5e-1, float 2.5e-01, float 2.5e-01>)
   ret <4 x float> %r
 }
 
 define <2 x double> @pow_v2f64_one_fourth_fmf(<2 x double> %x) nounwind {
 ; CHECK-LABEL: pow_v2f64_one_fourth_fmf:
 ; CHECK:       # %bb.0:

 ; CHECK-LABEL: pow_f64_not_enough_fmf:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    movsd {{.*#+}} xmm1 = mem[0],zero
 ; CHECK-NEXT:    jmp pow # TAILCALL
   %r = call nsz ninf afn double @llvm.pow.f64(double %x, double 0x3fd5555555555555)
   ret double %r
 }
 
+attributes #0 = { nounwind "denormal-fp-math"="ieee,preserve-sign" }

llvm/test/CodeGen/X86/sqrt-fastmath-mir.ll

 ; NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
 ; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx2,fma -stop-after=finalize-isel 2>&1 | FileCheck %s
 
-declare float @llvm.sqrt.f32(float) #0
+declare float @llvm.sqrt.f32(float) #2
 
-define float @foo(float %f) #0 {
-  ; CHECK-LABEL: name: foo
+define float @sqrt_ieee(float %f) #0 {
+  ; CHECK-LABEL: name: sqrt_ieee
+  ; CHECK: bb.0 (%ir-block.0):
+  ; CHECK:   liveins: $xmm0
+  ; CHECK:   [[COPY:%[0-9]+]]:fr32 = COPY $xmm0
+  ; CHECK:   [[DEF:%[0-9]+]]:fr32 = IMPLICIT_DEF
+  ; CHECK:   [[VRSQRTSSr:%[0-9]+]]:fr32 = VRSQRTSSr killed [[DEF]], [[COPY]]
+  ; CHECK:   %3:fr32 = nofpexcept VMULSSrr [[COPY]], [[VRSQRTSSr]], implicit $mxcsr
+  ; CHECK:   [[VMOVSSrm_alt:%[0-9]+]]:fr32 = VMOVSSrm_alt $rip, 1, $noreg, %const.0, $noreg :: (load 4 from constant-pool)
+  ; CHECK:   %5:fr32 = nofpexcept VFMADD213SSr [[VRSQRTSSr]], killed %3, [[VMOVSSrm_alt]], implicit $mxcsr
+  ; CHECK:   [[VMOVSSrm_alt1:%[0-9]+]]:fr32 = VMOVSSrm_alt $rip, 1, $noreg, %const.1, $noreg :: (load 4 from constant-pool)
+  ; CHECK:   %7:fr32 = nofpexcept VMULSSrr [[VRSQRTSSr]], [[VMOVSSrm_alt1]], implicit $mxcsr
+  ; CHECK:   %8:fr32 = nofpexcept VMULSSrr killed %7, killed %5, implicit $mxcsr
+  ; CHECK:   %9:fr32 = nofpexcept VMULSSrr [[COPY]], %8, implicit $mxcsr
+  ; CHECK:   %10:fr32 = nofpexcept VFMADD213SSr %8, %9, [[VMOVSSrm_alt]], implicit $mxcsr
+  ; CHECK:   %11:fr32 = nofpexcept VMULSSrr %9, [[VMOVSSrm_alt1]], implicit $mxcsr
+  ; CHECK:   %12:fr32 = nofpexcept VMULSSrr killed %11, killed %10, implicit $mxcsr
+  ; CHECK:   [[COPY1:%[0-9]+]]:vr128 = COPY %12
+  ; CHECK:   [[COPY2:%[0-9]+]]:vr128 = COPY [[COPY]]
+  ; CHECK:   [[VPBROADCASTDrm:%[0-9]+]]:vr128 = VPBROADCASTDrm $rip, 1, $noreg, %const.2, $noreg :: (load 4 from constant-pool)
+  ; CHECK:   [[VPANDrr:%[0-9]+]]:vr128 = VPANDrr killed [[COPY2]], killed [[VPBROADCASTDrm]]
+  ; CHECK:   [[COPY3:%[0-9]+]]:fr32 = COPY [[VPANDrr]]
+  ; CHECK:   %18:fr32 = nofpexcept VCMPSSrm killed [[COPY3]], $rip, 1, $noreg, %const.3, $noreg, 1, implicit $mxcsr :: (load 4 from constant-pool)
+  ; CHECK:   [[COPY4:%[0-9]+]]:vr128 = COPY %18
+  ; CHECK:   [[VPANDNrr:%[0-9]+]]:vr128 = VPANDNrr killed [[COPY4]], killed [[COPY1]]
+  ; CHECK:   [[COPY5:%[0-9]+]]:fr32 = COPY [[VPANDNrr]]
+  ; CHECK:   $xmm0 = COPY [[COPY5]]
+  ; CHECK:   RET 0, $xmm0
+  %call = tail call float @llvm.sqrt.f32(float %f)
+  ret float %call
+}
+
+define float @sqrt_daz(float %f) #1 {
+  ; CHECK-LABEL: name: sqrt_daz
   ; CHECK: bb.0 (%ir-block.0):
   ; CHECK:   liveins: $xmm0
   ; CHECK:   [[COPY:%[0-9]+]]:fr32 = COPY $xmm0
   ; CHECK:   [[DEF:%[0-9]+]]:fr32 = IMPLICIT_DEF
   ; CHECK:   [[VRSQRTSSr:%[0-9]+]]:fr32 = VRSQRTSSr killed [[DEF]], [[COPY]]
   ; CHECK:   %3:fr32 = nofpexcept VMULSSrr [[COPY]], [[VRSQRTSSr]], implicit $mxcsr
   ; CHECK:   [[VMOVSSrm_alt:%[0-9]+]]:fr32 = VMOVSSrm_alt $rip, 1, $noreg, %const.0, $noreg :: (load 4 from constant-pool)
   ; CHECK:   %5:fr32 = nofpexcept VFMADD213SSr [[VRSQRTSSr]], killed %3, [[VMOVSSrm_alt]], implicit $mxcsr
   ; CHECK:   [[VMOVSSrm_alt1:%[0-9]+]]:fr32 = VMOVSSrm_alt $rip, 1, $noreg, %const.1, $noreg :: (load 4 from constant-pool)
   ; CHECK:   %7:fr32 = nofpexcept VMULSSrr [[VRSQRTSSr]], [[VMOVSSrm_alt1]], implicit $mxcsr
   ; CHECK:   %8:fr32 = nofpexcept VMULSSrr killed %7, killed %5, implicit $mxcsr
   ; CHECK:   %9:fr32 = nofpexcept VMULSSrr [[COPY]], %8, implicit $mxcsr
   ; CHECK:   %10:fr32 = nofpexcept VFMADD213SSr %8, %9, [[VMOVSSrm_alt]], implicit $mxcsr
   ; CHECK:   %11:fr32 = nofpexcept VMULSSrr %9, [[VMOVSSrm_alt1]], implicit $mxcsr
   ; CHECK:   %12:fr32 = nofpexcept VMULSSrr killed %11, killed %10, implicit $mxcsr
   ; CHECK:   [[COPY1:%[0-9]+]]:vr128 = COPY %12
   ; CHECK:   [[FsFLD0SS:%[0-9]+]]:fr32 = FsFLD0SS
   ; CHECK:   %15:fr32 = nofpexcept VCMPSSrr [[COPY]], killed [[FsFLD0SS]], 0, implicit $mxcsr
   ; CHECK:   [[COPY2:%[0-9]+]]:vr128 = COPY %15
   ; CHECK:   [[VPANDNrr:%[0-9]+]]:vr128 = VPANDNrr killed [[COPY2]], killed [[COPY1]]
   ; CHECK:   [[COPY3:%[0-9]+]]:fr32 = COPY [[VPANDNrr]]
   ; CHECK:   $xmm0 = COPY [[COPY3]]
   ; CHECK:   RET 0, $xmm0
-  %call = tail call float @llvm.sqrt.f32(float %f) #1
+  %call = tail call float @llvm.sqrt.f32(float %f)
   ret float %call
 }
 
-define float @rfoo(float %f) #0 {
-  ; CHECK-LABEL: name: rfoo
+define float @rsqrt_ieee(float %f) #0 {
+  ; CHECK-LABEL: name: rsqrt_ieee
+  ; CHECK: bb.0 (%ir-block.0):
+  ; CHECK:   liveins: $xmm0
+  ; CHECK:   [[COPY:%[0-9]+]]:fr32 = COPY $xmm0
+  ; CHECK:   [[DEF:%[0-9]+]]:fr32 = IMPLICIT_DEF
+  ; CHECK:   [[VRSQRTSSr:%[0-9]+]]:fr32 = VRSQRTSSr killed [[DEF]], [[COPY]]
+  ; CHECK:   %3:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VMULSSrr [[COPY]], [[VRSQRTSSr]], implicit $mxcsr
+  ; CHECK:   [[VMOVSSrm_alt:%[0-9]+]]:fr32 = VMOVSSrm_alt $rip, 1, $noreg, %const.0, $noreg :: (load 4 from constant-pool)
+  ; CHECK:   %5:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VFMADD213SSr [[VRSQRTSSr]], killed %3, [[VMOVSSrm_alt]], implicit $mxcsr
+  ; CHECK:   [[VMOVSSrm_alt1:%[0-9]+]]:fr32 = VMOVSSrm_alt $rip, 1, $noreg, %const.1, $noreg :: (load 4 from constant-pool)
+  ; CHECK:   %7:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VMULSSrr [[VRSQRTSSr]], [[VMOVSSrm_alt1]], implicit $mxcsr
+  ; CHECK:   %8:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VMULSSrr killed %7, killed %5, implicit $mxcsr
+  ; CHECK:   %9:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VMULSSrr [[COPY]], %8, implicit $mxcsr
+  ; CHECK:   %10:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VFMADD213SSr %8, killed %9, [[VMOVSSrm_alt]], implicit $mxcsr
+  ; CHECK:   %11:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VMULSSrr %8, [[VMOVSSrm_alt1]], implicit $mxcsr
+  ; CHECK:   %12:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VMULSSrr killed %11, killed %10, implicit $mxcsr
+  ; CHECK:   $xmm0 = COPY %12
+  ; CHECK:   RET 0, $xmm0
+  %sqrt = tail call float @llvm.sqrt.f32(float %f)
+  %div = fdiv fast float 1.0, %sqrt
+  ret float %div
+}
+
+define float @rsqrt_daz(float %f) #1 {
+  ; CHECK-LABEL: name: rsqrt_daz
   ; CHECK: bb.0 (%ir-block.0):
   ; CHECK:   liveins: $xmm0
   ; CHECK:   [[COPY:%[0-9]+]]:fr32 = COPY $xmm0
   ; CHECK:   [[DEF:%[0-9]+]]:fr32 = IMPLICIT_DEF
   ; CHECK:   [[VRSQRTSSr:%[0-9]+]]:fr32 = VRSQRTSSr killed [[DEF]], [[COPY]]
   ; CHECK:   %3:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VMULSSrr [[COPY]], [[VRSQRTSSr]], implicit $mxcsr
   ; CHECK:   [[VMOVSSrm_alt:%[0-9]+]]:fr32 = VMOVSSrm_alt $rip, 1, $noreg, %const.0, $noreg :: (load 4 from constant-pool)
   ; CHECK:   %5:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VFMADD213SSr [[VRSQRTSSr]], killed %3, [[VMOVSSrm_alt]], implicit $mxcsr
   ; CHECK:   [[VMOVSSrm_alt1:%[0-9]+]]:fr32 = VMOVSSrm_alt $rip, 1, $noreg, %const.1, $noreg :: (load 4 from constant-pool)
   ; CHECK:   %7:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VMULSSrr [[VRSQRTSSr]], [[VMOVSSrm_alt1]], implicit $mxcsr
   ; CHECK:   %8:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VMULSSrr killed %7, killed %5, implicit $mxcsr
   ; CHECK:   %9:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VMULSSrr [[COPY]], %8, implicit $mxcsr
   ; CHECK:   %10:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VFMADD213SSr %8, killed %9, [[VMOVSSrm_alt]], implicit $mxcsr
   ; CHECK:   %11:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VMULSSrr %8, [[VMOVSSrm_alt1]], implicit $mxcsr
   ; CHECK:   %12:fr32 = nnan ninf nsz arcp contract afn reassoc nofpexcept VMULSSrr killed %11, killed %10, implicit $mxcsr
   ; CHECK:   $xmm0 = COPY %12
   ; CHECK:   RET 0, $xmm0
   %sqrt = tail call float @llvm.sqrt.f32(float %f)
   %div = fdiv fast float 1.0, %sqrt
   ret float %div
 }
 
-attributes #0 = { "unsafe-fp-math"="true" "reciprocal-estimates"="sqrt:2" }
-attributes #1 = { nounwind readnone }
+attributes #0 = { "unsafe-fp-math"="true" "reciprocal-estimates"="sqrt:2" "denormal-fp-math"="ieee,ieee" }
+attributes #1 = { "unsafe-fp-math"="true" "reciprocal-estimates"="sqrt:2" "denormal-fp-math"="ieee,preserve-sign" }
+attributes #2 = { nounwind readnone }

llvm/test/CodeGen/X86/sqrt-fastmath.ll

 ; AVX-LABEL: finite_f32_no_estimate:
 ; AVX:       # %bb.0:
 ; AVX-NEXT:    vsqrtss %xmm0, %xmm0, %xmm0
 ; AVX-NEXT:    retq
   %call = tail call float @__sqrtf_finite(float %f) #2
   ret float %call
 }
 
-define float @finite_f32_estimate(float %f) #1 {
-; SSE-LABEL: finite_f32_estimate:
+define float @finite_f32_estimate_ieee(float %f) #1 {
+; SSE-LABEL: finite_f32_estimate_ieee:
+; SSE:       # %bb.0:
+; SSE-NEXT:    rsqrtss %xmm0, %xmm1
+; SSE-NEXT:    movaps %xmm0, %xmm2
+; SSE-NEXT:    mulss %xmm1, %xmm2
+; SSE-NEXT:    movss {{.*#+}} xmm3 = mem[0],zero,zero,zero
+; SSE-NEXT:    mulss %xmm2, %xmm3
+; SSE-NEXT:    mulss %xmm1, %xmm2
+; SSE-NEXT:    addss {{.*}}(%rip), %xmm2
+; SSE-NEXT:    mulss %xmm3, %xmm2
+; SSE-NEXT:    andps {{.*}}(%rip), %xmm0
+; SSE-NEXT:    cmpltss {{.*}}(%rip), %xmm0
+; SSE-NEXT:    andnps %xmm2, %xmm0
+; SSE-NEXT:    retq
+;
+; AVX1-LABEL: finite_f32_estimate_ieee:
+; AVX1:       # %bb.0:
+; AVX1-NEXT:    vrsqrtss %xmm0, %xmm0, %xmm1
+; AVX1-NEXT:    vmulss %xmm1, %xmm0, %xmm2
+; AVX1-NEXT:    vmulss %xmm1, %xmm2, %xmm1
+; AVX1-NEXT:    vaddss {{.*}}(%rip), %xmm1, %xmm1
+; AVX1-NEXT:    vmulss {{.*}}(%rip), %xmm2, %xmm2
+; AVX1-NEXT:    vmulss %xmm1, %xmm2, %xmm1
+; AVX1-NEXT:    vandps {{.*}}(%rip), %xmm0, %xmm0
+; AVX1-NEXT:    vcmpltss {{.*}}(%rip), %xmm0, %xmm0
+; AVX1-NEXT:    vandnps %xmm1, %xmm0, %xmm0
+; AVX1-NEXT:    retq
+;
+; AVX512-LABEL: finite_f32_estimate_ieee:
+; AVX512:       # %bb.0:
+; AVX512-NEXT:    vrsqrtss %xmm0, %xmm0, %xmm1
+; AVX512-NEXT:    vmulss %xmm1, %xmm0, %xmm2
+; AVX512-NEXT:    vfmadd213ss {{.*#+}} xmm1 = (xmm2 * xmm1) + mem
+; AVX512-NEXT:    vmulss {{.*}}(%rip), %xmm2, %xmm2
+; AVX512-NEXT:    vmulss %xmm1, %xmm2, %xmm1
+; AVX512-NEXT:    vbroadcastss {{.*#+}} xmm2 = [NaN,NaN,NaN,NaN]
+; AVX512-NEXT:    vandps %xmm2, %xmm0, %xmm0
+; AVX512-NEXT:    vcmpltss {{.*}}(%rip), %xmm0, %k1
+; AVX512-NEXT:    vxorps %xmm0, %xmm0, %xmm0
+; AVX512-NEXT:    vmovss %xmm0, %xmm1, %xmm1 {%k1}
+; AVX512-NEXT:    vmovaps %xmm1, %xmm0
+; AVX512-NEXT:    retq
+  %call = tail call float @__sqrtf_finite(float %f) #2
+  ret float %call
+}
+
+define float @finite_f32_estimate_daz(float %f) #4 {
+; SSE-LABEL: finite_f32_estimate_daz:
 ; SSE:       # %bb.0:
 ; SSE-NEXT:    rsqrtss %xmm0, %xmm1
 ; SSE-NEXT:    movaps %xmm0, %xmm2
 ; SSE-NEXT:    mulss %xmm1, %xmm2
 ; SSE-NEXT:    movss {{.*#+}} xmm3 = mem[0],zero,zero,zero
 ; SSE-NEXT:    mulss %xmm2, %xmm3
 ; SSE-NEXT:    mulss %xmm1, %xmm2
 ; SSE-NEXT:    addss {{.*}}(%rip), %xmm2
 ; SSE-NEXT:    mulss %xmm3, %xmm2
 ; SSE-NEXT:    xorps %xmm1, %xmm1
 ; SSE-NEXT:    cmpeqss %xmm1, %xmm0
 ; SSE-NEXT:    andnps %xmm2, %xmm0
 ; SSE-NEXT:    retq
 ;
-; AVX1-LABEL: finite_f32_estimate:
+; AVX1-LABEL: finite_f32_estimate_daz:
 ; AVX1:       # %bb.0:
 ; AVX1-NEXT:    vrsqrtss %xmm0, %xmm0, %xmm1
 ; AVX1-NEXT:    vmulss %xmm1, %xmm0, %xmm2
 ; AVX1-NEXT:    vmulss %xmm1, %xmm2, %xmm1
 ; AVX1-NEXT:    vaddss {{.*}}(%rip), %xmm1, %xmm1
 ; AVX1-NEXT:    vmulss {{.*}}(%rip), %xmm2, %xmm2
 ; AVX1-NEXT:    vmulss %xmm1, %xmm2, %xmm1
 ; AVX1-NEXT:    vxorps %xmm2, %xmm2, %xmm2
 ; AVX1-NEXT:    vcmpeqss %xmm2, %xmm0, %xmm0
 ; AVX1-NEXT:    vandnps %xmm1, %xmm0, %xmm0
 ; AVX1-NEXT:    retq
 ;
-; AVX512-LABEL: finite_f32_estimate:
+; AVX512-LABEL: finite_f32_estimate_daz:
 ; AVX512:       # %bb.0:
 ; AVX512-NEXT:    vrsqrtss %xmm0, %xmm0, %xmm1
 ; AVX512-NEXT:    vmulss %xmm1, %xmm0, %xmm2
 ; AVX512-NEXT:    vfmadd213ss {{.*#+}} xmm1 = (xmm2 * xmm1) + mem
 ; AVX512-NEXT:    vmulss {{.*}}(%rip), %xmm2, %xmm2
 ; AVX512-NEXT:    vmulss %xmm1, %xmm2, %xmm1
 ; AVX512-NEXT:    vxorps %xmm2, %xmm2, %xmm2
 ; AVX512-NEXT:    vcmpeqss %xmm2, %xmm0, %k1
; AVX512-NEXT:    retq
   ret <16 x float> %div
 }
 
 
 attributes #0 = { "unsafe-fp-math"="true" "reciprocal-estimates"="!sqrtf,!vec-sqrtf,!divf,!vec-divf" }
 attributes #1 = { "unsafe-fp-math"="true" "reciprocal-estimates"="sqrt,vec-sqrt" }
 attributes #2 = { nounwind readnone }
 attributes #3 = { "unsafe-fp-math"="true" "reciprocal-estimates"="sqrt,vec-sqrt" "denormal-fp-math"="ieee" }
-
+attributes #4 = { "unsafe-fp-math"="true" "reciprocal-estimates"="sqrt,vec-sqrt" "denormal-fp-math"="ieee,preserve-sign" }