[llvm] 0385a18 - DAG: exp opcodes cannotBeOrderedNegativeFP (#167604)

[via llvm-commits]

Author: Matt Arsenault
Date: 2025-11-12T19:50:46Z
New Revision: 0385a182da7728aeb68fe1359a3d3298737ce6ef

URL: https://github.com/llvm/llvm-project/commit/0385a182da7728aeb68fe1359a3d3298737ce6ef
DIFF: https://github.com/llvm/llvm-project/commit/0385a182da7728aeb68fe1359a3d3298737ce6ef.diff

LOG: DAG: exp opcodes cannotBeOrderedNegativeFP (#167604)

Added: 
    

Modified: 
    llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
    llvm/test/CodeGen/AArch64/frem-power2.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 363c71d84694f..c2b4c19846316 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -6105,7 +6105,17 @@ bool SelectionDAG::cannotBeOrderedNegativeFP(SDValue Op) const {
   if (ConstantFPSDNode *C1 = isConstOrConstSplatFP(Op, true))
     return !C1->isNegative();
 
-  return Op.getOpcode() == ISD::FABS;
+  switch (Op.getOpcode()) {
+  case ISD::FABS:
+  case ISD::FEXP:
+  case ISD::FEXP2:
+  case ISD::FEXP10:
+    return true;
+  default:
+    return false;
+  }
+
+  llvm_unreachable("covered opcode switch");
 }
 
 bool SelectionDAG::isEqualTo(SDValue A, SDValue B) const {

diff  --git a/llvm/test/CodeGen/AArch64/frem-power2.ll b/llvm/test/CodeGen/AArch64/frem-power2.ll
index 52bc704eadc89..179df026e25d6 100644
--- a/llvm/test/CodeGen/AArch64/frem-power2.ll
+++ b/llvm/test/CodeGen/AArch64/frem-power2.ll
@@ -91,14 +91,10 @@ define float @frem2_exp(float %x) #0 {
 ; CHECK-SD-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
 ; CHECK-SD-NEXT:    bl expf
 ; CHECK-SD-NEXT:    fmov s1, #0.50000000
-; CHECK-SD-NEXT:    // kill: def $s0 killed $s0 def $q0
 ; CHECK-SD-NEXT:    fmov s2, #-2.00000000
 ; CHECK-SD-NEXT:    fmul s1, s0, s1
 ; CHECK-SD-NEXT:    frintz s1, s1
-; CHECK-SD-NEXT:    fmadd s1, s1, s2, s0
-; CHECK-SD-NEXT:    mvni v2.4s, #128, lsl #24
-; CHECK-SD-NEXT:    bit v0.16b, v1.16b, v2.16b
-; CHECK-SD-NEXT:    // kill: def $s0 killed $s0 killed $q0
+; CHECK-SD-NEXT:    fmadd s0, s1, s2, s0
 ; CHECK-SD-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
 ; CHECK-SD-NEXT:    ret
 ;
@@ -121,14 +117,10 @@ define float @frem2_exp2(float %x) #0 {
 ; CHECK-SD-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
 ; CHECK-SD-NEXT:    bl exp2f
 ; CHECK-SD-NEXT:    fmov s1, #0.50000000
-; CHECK-SD-NEXT:    // kill: def $s0 killed $s0 def $q0
 ; CHECK-SD-NEXT:    fmov s2, #-2.00000000
 ; CHECK-SD-NEXT:    fmul s1, s0, s1
 ; CHECK-SD-NEXT:    frintz s1, s1
-; CHECK-SD-NEXT:    fmadd s1, s1, s2, s0
-; CHECK-SD-NEXT:    mvni v2.4s, #128, lsl #24
-; CHECK-SD-NEXT:    bit v0.16b, v1.16b, v2.16b
-; CHECK-SD-NEXT:    // kill: def $s0 killed $s0 killed $q0
+; CHECK-SD-NEXT:    fmadd s0, s1, s2, s0
 ; CHECK-SD-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
 ; CHECK-SD-NEXT:    ret
 ;
@@ -151,14 +143,10 @@ define float @frem2_exp10(float %x) #0 {
 ; CHECK-SD-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
 ; CHECK-SD-NEXT:    bl exp10f
 ; CHECK-SD-NEXT:    fmov s1, #0.50000000
-; CHECK-SD-NEXT:    // kill: def $s0 killed $s0 def $q0
 ; CHECK-SD-NEXT:    fmov s2, #-2.00000000
 ; CHECK-SD-NEXT:    fmul s1, s0, s1
 ; CHECK-SD-NEXT:    frintz s1, s1
-; CHECK-SD-NEXT:    fmadd s1, s1, s2, s0
-; CHECK-SD-NEXT:    mvni v2.4s, #128, lsl #24
-; CHECK-SD-NEXT:    bit v0.16b, v1.16b, v2.16b
-; CHECK-SD-NEXT:    // kill: def $s0 killed $s0 killed $q0
+; CHECK-SD-NEXT:    fmadd s0, s1, s2, s0
 ; CHECK-SD-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
 ; CHECK-SD-NEXT:    ret
 ;