[llvm] 4e6783f - [DAG] getFreeze()/getNode() - account for operand depth when calling isGuaranteedNotToBeUndefOrPoison (PR57554)

[Simon Pilgrim via llvm-commits]

Author: Simon Pilgrim
Date: 2022-09-05T11:46:46+01:00
New Revision: 4e6783f8665252622f7514c63af1dc5b0242dabe

URL: https://github.com/llvm/llvm-project/commit/4e6783f8665252622f7514c63af1dc5b0242dabe
DIFF: https://github.com/llvm/llvm-project/commit/4e6783f8665252622f7514c63af1dc5b0242dabe.diff

LOG: [DAG] getFreeze()/getNode() - account for operand depth when calling isGuaranteedNotToBeUndefOrPoison (PR57554)

Similar to #57402 - we were calling isGuaranteedNotToBeUndefOrPoison on the freeze operand (with Depth = 0), but wasn't accounting for the fact that a later isGuaranteedNotToBeUndefOrPoison assertion will call from the new node (with Depth = 0 as well) - which will then recursively call isGuaranteedNotToBeUndefOrPoison for its operands with Depth = 1

Fixes #57554

Added: 
    llvm/test/CodeGen/X86/pr57554.ll

Modified: 
    llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

Removed: 
    


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diff  --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index cffdc3ace598..fa028cfdd2b3 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -5235,7 +5235,8 @@ SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
     break;
   case ISD::FREEZE:
     assert(VT == Operand.getValueType() && "Unexpected VT!");
-    if (isGuaranteedNotToBeUndefOrPoison(Operand))
+    if (isGuaranteedNotToBeUndefOrPoison(Operand, /*PoisonOnly*/ false,
+                                         /*Depth*/ 1))
       return Operand;
     break;
   case ISD::TokenFactor:

diff  --git a/llvm/test/CodeGen/X86/pr57554.ll b/llvm/test/CodeGen/X86/pr57554.ll
new file mode 100644
index 000000000000..0eb40979c355
--- /dev/null
+++ b/llvm/test/CodeGen/X86/pr57554.ll
@@ -0,0 +1,25 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-- | FileCheck %s
+
+ at a = external dso_local local_unnamed_addr global i8, align 1
+
+define void @PR57554() {
+; CHECK-LABEL: PR57554:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    movb %al, a(%rip)
+; CHECK-NEXT:    retq
+  %.fr13 = freeze i8 undef
+  %i = xor i8 %.fr13, -1
+  %not = sext i8 %i to i32
+  %add = add i32 %not, 2147483647
+  %or = or i32 %add, -1794967296
+  %or4 = or i32 %or, 0
+  %not5 = xor i32 %or4, -1
+  %sub = add nsw i32 0, -1
+  %add7 = add nsw i32 %sub, %not5
+  %add7.fr = freeze i32 %add7
+  %i1 = trunc i32 %add7.fr to i8
+  %conv10 = select i1 false, i8 0, i8 %i1
+  store i8 %conv10, ptr @a, align 1
+  ret void
+}