[llvm] 3c0735c - [X86] Call insertDAGNode on trunc/zext created in tryShiftAmountMod.

[Craig Topper via llvm-commits]

Author: Craig Topper
Date: 2021-05-24T10:23:22-07:00
New Revision: 3c0735c6d8d009dacdb6f63fd3164de54f7121cf

URL: https://github.com/llvm/llvm-project/commit/3c0735c6d8d009dacdb6f63fd3164de54f7121cf
DIFF: https://github.com/llvm/llvm-project/commit/3c0735c6d8d009dacdb6f63fd3164de54f7121cf.diff

LOG: [X86] Call insertDAGNode on trunc/zext created in tryShiftAmountMod.

This puts the new nodes in the proper place in the topologically
sorted list of nodes.

Fixes PR50431, which was introduced recently in D101944.

Added: 
    llvm/test/CodeGen/X86/pr50431.ll

Modified: 
    llvm/lib/Target/X86/X86ISelDAGToDAG.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index f3b4b8eeace6f..d692fa0fa492f 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -3867,8 +3867,12 @@ bool X86DAGToDAGISel::tryShiftAmountMod(SDNode *N) {
           Add1 = Add1.getOperand(0);
           SubVT = Add1.getValueType();
         }
-        X = CurDAG->getNode(ISD::ADD, DL, SubVT, Add1,
-                            CurDAG->getZExtOrTrunc(Add0, DL, SubVT));
+        if (Add0.getValueType() != SubVT) {
+          Add0 = CurDAG->getZExtOrTrunc(Add0, DL, SubVT);
+          insertDAGNode(*CurDAG, OrigShiftAmt, Add0);
+        }
+
+        X = CurDAG->getNode(ISD::ADD, DL, SubVT, Add1, Add0);
         insertDAGNode(*CurDAG, OrigShiftAmt, X);
       } else
         return false;

diff  --git a/llvm/test/CodeGen/X86/pr50431.ll b/llvm/test/CodeGen/X86/pr50431.ll
new file mode 100644
index 0000000000000..2b7ff93a935b4
--- /dev/null
+++ b/llvm/test/CodeGen/X86/pr50431.ll
@@ -0,0 +1,40 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+;RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu | FileCheck %s
+
+ at a = dso_local global i32 0, align 4
+
+; Function Attrs: nofree norecurse nounwind uwtable willreturn mustprogress
+define dso_local i32 @main() #0 {
+; CHECK-LABEL: main:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    movl $224, %ecx
+; CHECK-NEXT:    addl a(%rip), %ecx
+; CHECK-NEXT:    negl %ecx
+; CHECK-NEXT:    movl $2, %eax
+; CHECK-NEXT:    # kill: def $cl killed $cl killed $ecx
+; CHECK-NEXT:    shlq %cl, %rax
+; CHECK-NEXT:    testl %eax, %eax
+; CHECK-NEXT:    je .LBB0_1
+; CHECK-NEXT:  # %bb.2: # %lor.end
+; CHECK-NEXT:    xorl %eax, %eax
+; CHECK-NEXT:    retq
+; CHECK-NEXT:  .LBB0_1: # %lor.rhs
+; CHECK-NEXT:    movl a(%rip), %eax
+; CHECK-NEXT:    xorl %eax, %eax
+; CHECK-NEXT:    retq
+entry:
+  %0 = load volatile i32, i32* @a, align 4
+  %sub = sub i32 -32, %0
+  %sh_prom = zext i32 %sub to i64
+  %shl2 = shl i64 2, %sh_prom
+  %conv = trunc i64 %shl2 to i32
+  %tobool.not = icmp eq i32 %conv, 0
+  br i1 %tobool.not, label %lor.rhs, label %lor.end
+
+lor.rhs:                                          ; preds = %entry
+  %1 = load volatile i32, i32* @a, align 4
+  br label %lor.end
+
+lor.end:                                          ; preds = %lor.rhs, %entry
+  ret i32 0
+}