diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index 8ed291778da62..9187d49ca7a5a 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -2569,6 +2569,11 @@ static Constant *ConstantFoldScalarCall2(StringRef Name,
         break;
       case LibFunc_atan2:
       case LibFunc_atan2f:
+        // atan2(+/-0.0, +/-0.0) is known to raise an exception on some libm
+        // (Solaris), so we do not assume a known result for that.
+        if (Op1V.isZero() && Op2V.isZero())
+          return nullptr;
+        [[fallthrough]];
       case LibFunc_atan2_finite:
       case LibFunc_atan2f_finite:
         if (TLI->has(Func))
diff --git a/llvm/test/Transforms/EarlyCSE/atan.ll b/llvm/test/Transforms/EarlyCSE/atan.ll
index adb6ff7f5c03e..e665e0c9e54d9 100644
--- a/llvm/test/Transforms/EarlyCSE/atan.ll
+++ b/llvm/test/Transforms/EarlyCSE/atan.ll
@@ -55,7 +55,7 @@ define x86_fp80 @atanl_x86(x86_fp80 %x) {
 define float @callatan2_00() {
 ; CHECK-LABEL: @callatan2_00(
 ; CHECK-NEXT:    [[CALL:%.*]] = call float @atan2f(float 0.000000e+00, float 0.000000e+00)
-; CHECK-NEXT:    ret float 0.000000e+00
+; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @atan2f(float 0.0, float 0.0)
   ret float %call
@@ -66,7 +66,7 @@ define float @callatan2_00() {
 define float @callatan2_n00() {
 ; CHECK-LABEL: @callatan2_n00(
 ; CHECK-NEXT:    [[CALL:%.*]] = call float @atan2f(float -0.000000e+00, float 0.000000e+00)
-; CHECK-NEXT:    ret float -0.000000e+00
+; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @atan2f(float -0.0, float 0.0)
   ret float %call
@@ -77,7 +77,7 @@ define float @callatan2_n00() {
 define float @callatan2_0n0() {
 ; CHECK-LABEL: @callatan2_0n0(
 ; CHECK-NEXT:    [[CALL:%.*]] = call float @atan2f(float 0.000000e+00, float -0.000000e+00)
-; CHECK-NEXT:    ret float 0x400921FB60000000
+; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @atan2f(float 0.0, float -0.0)
   ret float %call
@@ -88,7 +88,7 @@ define float @callatan2_0n0() {
 define float @callatan2_n0n0() {
 ; CHECK-LABEL: @callatan2_n0n0(
 ; CHECK-NEXT:    [[CALL:%.*]] = call float @atan2f(float -0.000000e+00, float -0.000000e+00)
-; CHECK-NEXT:    ret float 0xC00921FB60000000
+; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @atan2f(float -0.0, float -0.0)
   ret float %call