diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 92577cd7517e6..e98d13486d023 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -5646,6 +5646,24 @@ void computeKnownFPClass(const Value *V, const APInt &DemandedElts,
     KnownFPClass KnownLHS, KnownRHS;
     computeKnownFPClass(Op->getOperand(1), DemandedElts, NeedForNan, KnownRHS,
                         Q, Depth + 1);
+
+    const APFloat *CRHS;
+    if (match(Op->getOperand(1), m_APFloat(CRHS))) {
+      // Match denormal scaling pattern, similar to the case in ldexp. If the
+      // constant's exponent is sufficiently large, the result cannot be
+      // subnormal.
+
+      // TODO: Should do general ConstantFPRange analysis.
+      const fltSemantics &Flt =
+          Op->getType()->getScalarType()->getFltSemantics();
+      unsigned Precision = APFloat::semanticsPrecision(Flt);
+      const int MantissaBits = Precision - 1;
+
+      int MinKnownExponent = ilogb(*CRHS);
+      if (MinKnownExponent >= MantissaBits)
+        Known.knownNot(fcSubnormal);
+    }
+
     if (!KnownRHS.isKnownNeverNaN())
       break;
 
diff --git a/llvm/test/Transforms/Attributor/nofpclass-fmul.ll b/llvm/test/Transforms/Attributor/nofpclass-fmul.ll
index 6d0edf0681ed4..0ad34105d4cb6 100644
--- a/llvm/test/Transforms/Attributor/nofpclass-fmul.ll
+++ b/llvm/test/Transforms/Attributor/nofpclass-fmul.ll
@@ -35,7 +35,7 @@ define float @ret_mul_exponent_f32_22(float %arg0) {
 }
 
 define float @ret_mul_exponent_f32_23(float %arg0) {
-; CHECK-LABEL: define float @ret_mul_exponent_f32_23(
+; CHECK-LABEL: define nofpclass(sub) float @ret_mul_exponent_f32_23(
 ; CHECK-SAME: float [[ARG0:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[CALL:%.*]] = fmul float [[ARG0]], 0x4160000000000000
 ; CHECK-NEXT:    ret float [[CALL]]
@@ -45,7 +45,7 @@ define float @ret_mul_exponent_f32_23(float %arg0) {
 }
 
 define float @ret_mul_exponent_f32_24(float %arg0) {
-; CHECK-LABEL: define float @ret_mul_exponent_f32_24(
+; CHECK-LABEL: define nofpclass(sub) float @ret_mul_exponent_f32_24(
 ; CHECK-SAME: float [[ARG0:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[CALL:%.*]] = fmul float [[ARG0]], 0x4170000000000000
 ; CHECK-NEXT:    ret float [[CALL]]
@@ -55,7 +55,7 @@ define float @ret_mul_exponent_f32_24(float %arg0) {
 }
 
 define float @ret_mul_exponent_f32_23_nnan(float nofpclass(nan) %arg0) {
-; CHECK-LABEL: define nofpclass(nan) float @ret_mul_exponent_f32_23_nnan(
+; CHECK-LABEL: define nofpclass(nan sub) float @ret_mul_exponent_f32_23_nnan(
 ; CHECK-SAME: float nofpclass(nan) [[ARG0:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[CALL:%.*]] = fmul float [[ARG0]], 0x4160000000000000
 ; CHECK-NEXT:    ret float [[CALL]]
@@ -85,7 +85,7 @@ define double @ret_mul_exponent_f64_51(double %arg0) {
 }
 
 define double @ret_mul_exponent_f64_52(double %arg0) {
-; CHECK-LABEL: define double @ret_mul_exponent_f64_52(
+; CHECK-LABEL: define nofpclass(sub) double @ret_mul_exponent_f64_52(
 ; CHECK-SAME: double [[ARG0:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[CALL:%.*]] = fmul double [[ARG0]], 0x4330000000000000
 ; CHECK-NEXT:    ret double [[CALL]]
@@ -95,7 +95,7 @@ define double @ret_mul_exponent_f64_52(double %arg0) {
 }
 
 define double @ret_mul_exponent_f64_53(double %arg0) {
-; CHECK-LABEL: define double @ret_mul_exponent_f64_53(
+; CHECK-LABEL: define nofpclass(sub) double @ret_mul_exponent_f64_53(
 ; CHECK-SAME: double [[ARG0:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[CALL:%.*]] = fmul double [[ARG0]], 0x4340000000000000
 ; CHECK-NEXT:    ret double [[CALL]]
@@ -125,7 +125,7 @@ define half @ret_mul_exponent_f16_9(half %arg0) {
 }
 
 define half @ret_mul_exponent_f16_10(half %arg0) {
-; CHECK-LABEL: define half @ret_mul_exponent_f16_10(
+; CHECK-LABEL: define nofpclass(sub) half @ret_mul_exponent_f16_10(
 ; CHECK-SAME: half [[ARG0:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[CALL:%.*]] = fmul half [[ARG0]], 0xH6400
 ; CHECK-NEXT:    ret half [[CALL]]
@@ -145,7 +145,7 @@ define bfloat @ret_mul_exponent_bf16_6(bfloat %arg0) {
 }
 
 define bfloat @ret_mul_exponent_bf16_7(bfloat %arg0) {
-; CHECK-LABEL: define bfloat @ret_mul_exponent_bf16_7(
+; CHECK-LABEL: define nofpclass(sub) bfloat @ret_mul_exponent_bf16_7(
 ; CHECK-SAME: bfloat [[ARG0:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[CALL:%.*]] = fmul bfloat [[ARG0]], 0xR4300
 ; CHECK-NEXT:    ret bfloat [[CALL]]
@@ -155,7 +155,7 @@ define bfloat @ret_mul_exponent_bf16_7(bfloat %arg0) {
 }
 
 define bfloat @ret_mul_exponent_bf16_8(bfloat %arg0) {
-; CHECK-LABEL: define bfloat @ret_mul_exponent_bf16_8(
+; CHECK-LABEL: define nofpclass(sub) bfloat @ret_mul_exponent_bf16_8(
 ; CHECK-SAME: bfloat [[ARG0:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[CALL:%.*]] = fmul bfloat [[ARG0]], 0xR4380
 ; CHECK-NEXT:    ret bfloat [[CALL]]
@@ -215,7 +215,7 @@ define float @ret_mul_exponent_f32_neg127(float %arg0) {
 }
 
 define <2 x float> @ret_mul_exponent_v2f32_splat_23(<2 x float> %arg0) {
-; CHECK-LABEL: define <2 x float> @ret_mul_exponent_v2f32_splat_23(
+; CHECK-LABEL: define nofpclass(sub) <2 x float> @ret_mul_exponent_v2f32_splat_23(
 ; CHECK-SAME: <2 x float> [[ARG0:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[CALL:%.*]] = fmul <2 x float> [[ARG0]], splat (float 0x4160000000000000)
 ; CHECK-NEXT:    ret <2 x float> [[CALL]]
@@ -267,7 +267,7 @@ define float @ret_mul_f32_0(float %arg0) {
 }
 
 define float @ret_mul_f32_inf(float %arg0) {
-; CHECK-LABEL: define float @ret_mul_f32_inf(
+; CHECK-LABEL: define nofpclass(sub) float @ret_mul_f32_inf(
 ; CHECK-SAME: float [[ARG0:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[CALL:%.*]] = fmul float [[ARG0]], 0x7FF0000000000000
 ; CHECK-NEXT:    ret float [[CALL]]
diff --git a/llvm/test/Transforms/Attributor/nofpclass-nan-fmul.ll b/llvm/test/Transforms/Attributor/nofpclass-nan-fmul.ll
index fbf6c2e0981fb..f6bb1354cb74f 100644
--- a/llvm/test/Transforms/Attributor/nofpclass-nan-fmul.ll
+++ b/llvm/test/Transforms/Attributor/nofpclass-nan-fmul.ll
@@ -195,7 +195,7 @@ define float @ret_fmul_square_nnan_nzero(float nofpclass(nan zero) %arg) #0 {
 }
 
 define float @ret_fmul_ieee_inf(float %arg) {
-; CHECK-LABEL: define float @ret_fmul_ieee_inf
+; CHECK-LABEL: define nofpclass(sub) float @ret_fmul_ieee_inf
 ; CHECK-SAME: (float [[ARG:%.*]]) #[[ATTR4:[0-9]+]] {
 ; CHECK-NEXT:    [[FMUL:%.*]] = fmul float [[ARG]], 0x7FF0000000000000
 ; CHECK-NEXT:    ret float [[FMUL]]