[llvm-branch-commits] [llvm] InstCombine: Fold known-qnan results to a literal nan (PR #176123)

via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Thu Jan 15 05:56:43 PST 2026 

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Matt Arsenault (arsenm)

<details>
<summary>Changes</summary>

Previously we only considered fcNan to fold to qnan for canonicalizing
results, ignoring the simpler case where we know the nan is already
quiet.

---

Patch is 21.96 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/176123.diff


18 Files Affected:

- (modified) llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp (+2) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-exp.ll (+1-1) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-extractelement.ll (+1-2) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fadd.ll (+1-2) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fmul.ll (+2-4) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fpext.ll (+1-2) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fptrunc-round.ll (+1-2) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fptrunc.ll (+1-2) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-frexp.ll (+3-4) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-insertelement.ll (+3-4) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-maximum.ll (+1-2) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-maximumnum.ll (+1-2) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-minimum.ll (+1-2) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-minimumnum.ll (+1-2) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-rounding-intrinsics.ll (+1-2) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-shufflevector.ll (+3-4) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-sqrt.ll (+3-9) 
- (modified) llvm/test/Transforms/InstCombine/simplify-demanded-fpclass.ll (+1-1) 


``````````diff
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index 1fc298dfc52a2..9f32e4fef1c3d 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -2028,6 +2028,8 @@ static Constant *getFPClassConstant(Type *Ty, FPClassTest Mask,
     return ConstantFP::getInfinity(Ty);
   case fcNegInf:
     return ConstantFP::getInfinity(Ty, true);
+  case fcQNan:
+    return ConstantFP::getQNaN(Ty);
   default:
     return nullptr;
   }
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-exp.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-exp.ll
index ef68699c73166..2a33ff195911e 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-exp.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-exp.ll
@@ -490,7 +490,7 @@ define nofpclass(nzero) float @source_is_known_snan(float nofpclass(inf norm sub
 define nofpclass(nzero) float @source_is_known_qnan(float nofpclass(inf norm sub zero snan) %must.be.qnan) {
 ; CHECK-LABEL: define nofpclass(nzero) float @source_is_known_qnan(
 ; CHECK-SAME: float nofpclass(snan inf zero sub norm) [[MUST_BE_QNAN:%.*]]) {
-; CHECK-NEXT:    ret float [[MUST_BE_QNAN]]
+; CHECK-NEXT:    ret float 0x7FF8000000000000
 ;
   %exp = call float @llvm.exp2.f32(float %must.be.qnan)
   ret float %exp
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-extractelement.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-extractelement.ll
index e571774c72f2b..6cabee258d2b6 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-extractelement.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-extractelement.ll
@@ -17,8 +17,7 @@ define nofpclass(inf norm sub zero) half @ret_only_nan__extractelement_unknown(<
 define nofpclass(snan inf norm sub zero) half @ret_only_qnan__extractelement_unknown(<4 x half> %vec, i32 %idx) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) half @ret_only_qnan__extractelement_unknown(
 ; CHECK-SAME: <4 x half> [[VEC:%.*]], i32 [[IDX:%.*]]) {
-; CHECK-NEXT:    [[EXT:%.*]] = extractelement <4 x half> [[VEC]], i32 [[IDX]]
-; CHECK-NEXT:    ret half [[EXT]]
+; CHECK-NEXT:    ret half 0xH7E00
 ;
   %ext = extractelement <4 x half> %vec, i32 %idx
   ret half %ext
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fadd.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fadd.ll
index 099624e912912..4386d22f82df4 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fadd.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fadd.ll
@@ -43,8 +43,7 @@ define nofpclass(inf zero sub norm) half @ret_only_nan(half %x, half %y) {
 define nofpclass(snan inf zero sub norm) half @ret_only_qnan(half %x, half %y) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) half @ret_only_qnan(
 ; CHECK-SAME: half [[X:%.*]], half [[Y:%.*]]) {
-; CHECK-NEXT:    [[ADD:%.*]] = fadd half [[X]], [[Y]]
-; CHECK-NEXT:    ret half [[ADD]]
+; CHECK-NEXT:    ret half 0xH7E00
 ;
   %add = fadd half %x, %y
   ret half %add
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fmul.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fmul.ll
index 4ed2e781a30d5..b5ad0ad4cafe3 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fmul.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fmul.ll
@@ -112,8 +112,7 @@ define nofpclass(inf norm sub zero) float @ret_only_nan_results_square(float nou
 define nofpclass(inf norm sub zero snan) float @ret_only_qnan_results_square(float noundef %x) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) float @ret_only_qnan_results_square(
 ; CHECK-SAME: float noundef [[X:%.*]]) {
-; CHECK-NEXT:    [[MUL:%.*]] = fmul float [[X]], [[X]]
-; CHECK-NEXT:    ret float [[MUL]]
+; CHECK-NEXT:    ret float 0x7FF8000000000000
 ;
   %mul = fmul float %x, %x
   ret float %mul
@@ -885,8 +884,7 @@ define nofpclass(inf norm sub zero) float @ret_only_nan_results_fmul(float %x, f
 define nofpclass(inf norm sub zero snan) float @ret_only_qnan_results_fmul(float %x, float %y) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) float @ret_only_qnan_results_fmul(
 ; CHECK-SAME: float [[X:%.*]], float [[Y:%.*]]) {
-; CHECK-NEXT:    [[MUL:%.*]] = fmul float [[X]], [[Y]]
-; CHECK-NEXT:    ret float [[MUL]]
+; CHECK-NEXT:    ret float 0x7FF8000000000000
 ;
   %mul = fmul float %x, %y
   ret float %mul
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fpext.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fpext.ll
index c1070954a26ff..7334277750d7e 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fpext.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fpext.ll
@@ -36,8 +36,7 @@ define nofpclass(inf norm sub zero qnan) float @ret_only_snan__fpext(half %x) {
 define nofpclass(inf norm sub zero snan) float @ret_only_qnan__fpext(half %x) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) float @ret_only_qnan__fpext(
 ; CHECK-SAME: half [[X:%.*]]) {
-; CHECK-NEXT:    [[RESULT:%.*]] = fpext half [[X]] to float
-; CHECK-NEXT:    ret float [[RESULT]]
+; CHECK-NEXT:    ret float 0x7FF8000000000000
 ;
   %result = fpext half %x to float
   ret float %result
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fptrunc-round.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fptrunc-round.ll
index 9ca3956be5358..33fe7977701ab 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fptrunc-round.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fptrunc-round.ll
@@ -40,8 +40,7 @@ define nofpclass(inf norm sub zero qnan) half @ret_only_snan__fptrunc(float %x)
 define nofpclass(inf norm sub zero snan) half @ret_only_qnan__fptrunc(float %x) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) half @ret_only_qnan__fptrunc(
 ; CHECK-SAME: float [[X:%.*]]) {
-; CHECK-NEXT:    [[RESULT:%.*]] = call half @llvm.fptrunc.round.f16.f32(float [[X]], metadata !"round.downward")
-; CHECK-NEXT:    ret half [[RESULT]]
+; CHECK-NEXT:    ret half 0xH7E00
 ;
   %result = call half @llvm.fptrunc.round.f16.f32(float %x, metadata !"round.downward")
   ret half %result
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fptrunc.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fptrunc.ll
index c1d5dacbc26c9..2edb04956d407 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fptrunc.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-fptrunc.ll
@@ -40,8 +40,7 @@ define nofpclass(inf norm sub zero qnan) half @ret_only_snan__fptrunc(float %x)
 define nofpclass(inf norm sub zero snan) half @ret_only_qnan__fptrunc(float %x) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) half @ret_only_qnan__fptrunc(
 ; CHECK-SAME: float [[X:%.*]]) {
-; CHECK-NEXT:    [[RESULT:%.*]] = fptrunc float [[X]] to half
-; CHECK-NEXT:    ret half [[RESULT]]
+; CHECK-NEXT:    ret half 0xH7E00
 ;
   %result = fptrunc float %x to half
   ret half %result
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-frexp.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-frexp.ll
index 75591556fc1e7..18977a10139dd 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-frexp.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-frexp.ll
@@ -65,7 +65,7 @@ define nofpclass(nan) half @extractvalue_not_frexp() {
 define nofpclass(snan inf norm sub zero) half @ret_only_qnan__frexp(half %unknown) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) half @ret_only_qnan__frexp(
 ; CHECK-SAME: half [[UNKNOWN:%.*]]) {
-; CHECK-NEXT:    ret half [[UNKNOWN]]
+; CHECK-NEXT:    ret half 0xH7E00
 ;
   %frexp = call { half, i32 } @llvm.frexp.f16.i32(half %unknown)
   %frexp.mant = extractvalue { half, i32 } %frexp, 0
@@ -296,8 +296,7 @@ define nofpclass(qnan) half @ret_nofpclass_qnan__frexp_select_unknown_qnan(i1 %c
 ; CHECK-LABEL: define nofpclass(qnan) half @ret_nofpclass_qnan__frexp_select_unknown_qnan(
 ; CHECK-SAME: i1 [[COND:%.*]], half [[UNKNOWN:%.*]]) {
 ; CHECK-NEXT:    [[ONLY_QNAN:%.*]] = call half @returns_qnan()
-; CHECK-NEXT:    [[SELECT:%.*]] = select i1 [[COND]], half [[UNKNOWN]], half [[ONLY_QNAN]]
-; CHECK-NEXT:    [[FREXP:%.*]] = call { half, i32 } @llvm.frexp.f16.i32(half [[SELECT]])
+; CHECK-NEXT:    [[FREXP:%.*]] = call { half, i32 } @llvm.frexp.f16.i32(half [[UNKNOWN]])
 ; CHECK-NEXT:    [[FREXP_MANT:%.*]] = extractvalue { half, i32 } [[FREXP]], 0
 ; CHECK-NEXT:    ret half [[FREXP_MANT]]
 ;
@@ -513,7 +512,7 @@ define nofpclass(snan) half @src_only_inf__frexp() {
 define nofpclass(snan) half @src_only_nan__frexp() {
 ; CHECK-LABEL: define nofpclass(snan) half @src_only_nan__frexp() {
 ; CHECK-NEXT:    [[ONLY_NAN:%.*]] = call half @returns_nan()
-; CHECK-NEXT:    ret half [[ONLY_NAN]]
+; CHECK-NEXT:    ret half 0xH7E00
 ;
   %only.nan = call half @returns_nan()
   %frexp = call { half, i32 } @llvm.frexp.f16.i32(half %only.nan)
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-insertelement.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-insertelement.ll
index 36d8766d967aa..8c6679d8be038 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-insertelement.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-insertelement.ll
@@ -29,8 +29,7 @@ define nofpclass(qnan inf zero sub norm) <4 x half> @ret_only_snan__insert_unkno
 define nofpclass(snan inf zero sub norm) <4 x half> @ret_only_qnan__insert_unknown_unknown(<4 x half> %vec, half %elt, i32 %idx) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) <4 x half> @ret_only_qnan__insert_unknown_unknown(
 ; CHECK-SAME: <4 x half> [[VEC:%.*]], half [[ELT:%.*]], i32 [[IDX:%.*]]) {
-; CHECK-NEXT:    [[INSERT:%.*]] = insertelement <4 x half> [[VEC]], half [[ELT]], i32 [[IDX]]
-; CHECK-NEXT:    ret <4 x half> [[INSERT]]
+; CHECK-NEXT:    ret <4 x half> splat (half 0xH7E00)
 ;
   %insert = insertelement <4 x half> %vec, half %elt, i32 %idx
   ret <4 x half> %insert
@@ -160,7 +159,7 @@ define nofpclass(snan) <4 x half> @insert_unknown_taints_known_nan_vector_input(
 ; CHECK-LABEL: define nofpclass(snan) <4 x half> @insert_unknown_taints_known_nan_vector_input(
 ; CHECK-SAME: half [[UNKNOWN_ELT:%.*]], i32 [[IDX:%.*]]) {
 ; CHECK-NEXT:    [[NAN_VEC:%.*]] = call <4 x half> @returns_nan()
-; CHECK-NEXT:    [[INSERT:%.*]] = insertelement <4 x half> [[NAN_VEC]], half [[UNKNOWN_ELT]], i32 [[IDX]]
+; CHECK-NEXT:    [[INSERT:%.*]] = insertelement <4 x half> splat (half 0xH7E00), half [[UNKNOWN_ELT]], i32 [[IDX]]
 ; CHECK-NEXT:    [[EXP:%.*]] = call <4 x half> @llvm.exp.v4f16(<4 x half> [[INSERT]])
 ; CHECK-NEXT:    ret <4 x half> [[EXP]]
 ;
@@ -175,7 +174,7 @@ define nofpclass(snan) <4 x half> @insert_unknown_vector_taints_known_nan_vector
 ; CHECK-LABEL: define nofpclass(snan) <4 x half> @insert_unknown_vector_taints_known_nan_vector_insert(
 ; CHECK-SAME: <4 x half> [[UNKNOWN_VEC:%.*]], i32 [[IDX:%.*]]) {
 ; CHECK-NEXT:    [[NAN_ELT:%.*]] = call half @returns_nan_f16()
-; CHECK-NEXT:    [[INSERT:%.*]] = insertelement <4 x half> [[UNKNOWN_VEC]], half [[NAN_ELT]], i32 [[IDX]]
+; CHECK-NEXT:    [[INSERT:%.*]] = insertelement <4 x half> [[UNKNOWN_VEC]], half 0xH7E00, i32 [[IDX]]
 ; CHECK-NEXT:    [[EXP:%.*]] = call <4 x half> @llvm.exp.v4f16(<4 x half> [[INSERT]])
 ; CHECK-NEXT:    ret <4 x half> [[EXP]]
 ;
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-maximum.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-maximum.ll
index 4c0f2f9d7ae78..b6a6e63af8acb 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-maximum.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-maximum.ll
@@ -68,8 +68,7 @@ define nofpclass(inf norm sub zero qnan) float @ret_only_snan(float %x, float %y
 define nofpclass(inf norm sub zero snan) float @ret_only_qnan(float %x, float %y) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) float @ret_only_qnan(
 ; CHECK-SAME: float [[X:%.*]], float [[Y:%.*]]) {
-; CHECK-NEXT:    [[RESULT:%.*]] = call nsz float @llvm.maximum.f32(float [[X]], float [[Y]])
-; CHECK-NEXT:    ret float [[RESULT]]
+; CHECK-NEXT:    ret float 0x7FF8000000000000
 ;
   %result = call float @llvm.maximum.f32(float %x, float %y)
   ret float %result
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-maximumnum.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-maximumnum.ll
index 4c87ca17a3512..2589d80a256d6 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-maximumnum.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-maximumnum.ll
@@ -67,8 +67,7 @@ define nofpclass(inf norm sub zero qnan) float @ret_only_snan(float %x, float %y
 define nofpclass(inf norm sub zero snan) float @ret_only_qnan(float %x, float %y) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) float @ret_only_qnan(
 ; CHECK-SAME: float [[X:%.*]], float [[Y:%.*]]) {
-; CHECK-NEXT:    [[RESULT:%.*]] = call nsz float @llvm.maximumnum.f32(float [[X]], float [[Y]])
-; CHECK-NEXT:    ret float [[RESULT]]
+; CHECK-NEXT:    ret float 0x7FF8000000000000
 ;
   %result = call float @llvm.maximumnum.f32(float %x, float %y)
   ret float %result
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-minimum.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-minimum.ll
index e62ec503c78ab..fba6e9c45da4d 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-minimum.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-minimum.ll
@@ -67,8 +67,7 @@ define nofpclass(inf norm sub zero qnan) float @ret_only_snan(float %x, float %y
 define nofpclass(inf norm sub zero snan) float @ret_only_qnan(float %x, float %y) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) float @ret_only_qnan(
 ; CHECK-SAME: float [[X:%.*]], float [[Y:%.*]]) {
-; CHECK-NEXT:    [[RESULT:%.*]] = call nsz float @llvm.minimum.f32(float [[X]], float [[Y]])
-; CHECK-NEXT:    ret float [[RESULT]]
+; CHECK-NEXT:    ret float 0x7FF8000000000000
 ;
   %result = call float @llvm.minimum.f32(float %x, float %y)
   ret float %result
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-minimumnum.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-minimumnum.ll
index e66e3afb52c77..b67077cb7dbd9 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-minimumnum.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-minimumnum.ll
@@ -67,8 +67,7 @@ define nofpclass(inf norm sub zero qnan) float @ret_only_snan(float %x, float %y
 define nofpclass(inf norm sub zero snan) float @ret_only_qnan(float %x, float %y) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) float @ret_only_qnan(
 ; CHECK-SAME: float [[X:%.*]], float [[Y:%.*]]) {
-; CHECK-NEXT:    [[RESULT:%.*]] = call nsz float @llvm.minimumnum.f32(float [[X]], float [[Y]])
-; CHECK-NEXT:    ret float [[RESULT]]
+; CHECK-NEXT:    ret float 0x7FF8000000000000
 ;
   %result = call float @llvm.minimumnum.f32(float %x, float %y)
   ret float %result
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-rounding-intrinsics.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-rounding-intrinsics.ll
index 1d8a08170677f..d1642569c6610 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-rounding-intrinsics.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-rounding-intrinsics.ll
@@ -42,8 +42,7 @@ define nofpclass(inf norm sub zero qnan) float @ret_only_snan__floor(float %x) {
 define nofpclass(inf norm sub zero snan) float @ret_only_qnan__floor(float %x) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) float @ret_only_qnan__floor(
 ; CHECK-SAME: float [[X:%.*]]) {
-; CHECK-NEXT:    [[RESULT:%.*]] = call float @llvm.floor.f32(float [[X]])
-; CHECK-NEXT:    ret float [[RESULT]]
+; CHECK-NEXT:    ret float 0x7FF8000000000000
 ;
   %result = call float @llvm.floor.f32(float %x)
   ret float %result
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-shufflevector.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-shufflevector.ll
index ee8be3ca1bf89..565e9b76ddea3 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-shufflevector.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-shufflevector.ll
@@ -28,8 +28,7 @@ define nofpclass(qnan inf zero sub norm) <4 x half> @ret_only_snan__shufflevecto
 define nofpclass(snan inf zero sub norm) <4 x half> @ret_only_qnan__shufflevector_unknown(<4 x half> %vec0, <4 x half> %vec1) {
 ; CHECK-LABEL: define nofpclass(snan inf zero sub norm) <4 x half> @ret_only_qnan__shufflevector_unknown(
 ; CHECK-SAME: <4 x half> [[VEC0:%.*]], <4 x half> [[VEC1:%.*]]) {
-; CHECK-NEXT:    [[SHUFFLE:%.*]] = shufflevector <4 x half> [[VEC0]], <4 x half> [[VEC1]], <4 x i32> <i32 6, i32 2, i32 3, i32 0>
-; CHECK-NEXT:    ret <4 x half> [[SHUFFLE]]
+; CHECK-NEXT:    ret <4 x half> splat (half 0xH7E00)
 ;
   %shuffle = shufflevector <4 x half> %vec0, <4 x half> %vec1, <4 x i32> <i32 6, i32 2, i32 3, i32 0>
   ret <4 x half> %shuffle
@@ -242,7 +241,7 @@ define nofpclass(snan) <4 x half> @ret_nonnan_rhs_taints_known_nan_result(i1 %co
 ; CHECK-LABEL: define nofpclass(snan) <4 x half> @ret_nonnan_rhs_taints_known_nan_result(
 ; CHECK-SAME: i1 [[COND:%.*]], <4 x half> [[UNKNOWN:%.*]]) {
 ; CHECK-NEXT:    [[NAN:%.*]] = call <4 x half> @returns_nan()
-; CHECK-NEXT:    [[SHUFFLE:%.*]] = shufflevector <4 x half> [[NAN]], <4 x half> [[UNKNOWN]], <4 x i32> <i32 5, i32 0, i32 1, i32 3>
+; CHECK-NEXT:    [[SHUFFLE:%.*]] = shufflevector <4 x half> <half 0xH7E00, half 0xH7E00, half poison, half 0xH7E00>, <4 x half> [[UNKNOWN]], <4 x i32> <i32 5, i32 0, i32 1, i32 3>
 ; CHECK-NEXT:    [[EXP:%.*]] = call <4 x half> @llvm.exp.v4f16(<4 x half> [[SHUFFLE]])
 ; CHECK-NEXT:    ret <4 x half> [[EXP]]
 ;
@@ -257,7 +256,7 @@ define nofpclass(snan) <4 x half> @ret_nonnan_lhs_taints_known_nan_result(i1 %co
 ; CHECK-LABEL: define nofpclass(snan) <4 x half> @ret_nonnan_lhs_taints_known_nan_result(
 ; CHECK-SAME: i1 [[COND:%.*]], <4 x half> [[UNKNOWN:%.*]]) {
 ; CHECK-NEXT:    [[NAN:%.*]] = call <4 x half> @returns_nan()
-; CHECK-NEXT:    [[SHUFFLE:%.*]] = shufflevector <4 x half> [[UNKNOWN]], <4 x half> [[NAN]], <4 x i32> <i32 5, i32 0, i32 1, i32 3>
+; CHECK-NEXT:    [[SHUFFLE:%.*]] = shufflevector <4 x half> [[UNKNOWN]], <4 x half> <half poison, half 0xH7E00, half poison, half poison>, <4 x i32> <i32 5, i32 0, i32 1, i32 3>
 ; CHECK-NEXT:    [[EXP:%.*]] = call <4 x half> @llvm.exp.v4f16(<4 x half> [[SHUFFLE]])
 ; CHECK-NEXT:    ret <4 x half> [[EXP]]
 ;
diff --git a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-sqrt.ll b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-sqrt.ll
index b09faf0f4c3af..0520fef0f0e79 100644
--- a/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-sqrt.ll
+++ b/llvm/test/Transforms/InstCombine/simplify-demanded-fpclass-sqrt.ll
@@ -163,9 +163,7 @@ define nofpclass(inf norm zero) float @ret_only_nan_or_sub__sqrt__select_unknown
 ; CHECK-LABEL: define nofpclass(inf zero norm) float @ret_only_nan_or_sub__sqrt__select_unknown_or_maybe_ninf(
 ; CHECK-SAME: i1 [[COND:%.*]], float nofpclass(nan) [[X:%.*]]) {
 ; CHECK-NEXT:    [[MAYBE_NINF:%.*]] = call nofpclass(nan pinf sub norm) float @func()
-; CHECK-NEXT:    [[SELECT:%.*]] = select i1 [[COND]], float [[X]], float 0xFFF0000000000000
-; CHECK-NEXT:    [[RESULT:%.*]] = call float @llvm.sqrt.f32(float [[SELECT]])
-; CHECK-NEXT:    ret float [[RESULT]]
+; CHECK-NEXT:    ret float 0x7FF8000000000000
 ;
   %maybe.ninf = call nofpclass(pinf norm sub nan) float @func()
   %select = select i1 %cond, float %x, float %maybe.ninf
@@ -178,9 +176,7 @@ define nofpclass(inf norm zero) float @ret_only_nan_or_sub__sqrt__select_unknown
 ; CHECK-LABEL: define nofpclass(inf zero norm) float @ret_only_nan_or_sub__sqrt__select_unknown_or_maybe_nnorm(
 ; CHECK-SAME: i1 [[COND:%.*]], float nofpclass(nan) [[X:%.*]]) {
 ; CHECK-NEXT:    [[MAYBE_NNORM:%.*]] = call nofpcl...
[truncated]

``````````

</details>


https://github.com/llvm/llvm-project/pull/176123

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