[ConstantFold] Constant fold icmp of boolean scalable vectors (#142528)

Closes #142447.

Author: dtcxzyw

llvm/lib/IR/ConstantFold.cpp

@@ -1149,10 +1149,10 @@ Constant *llvm::ConstantFoldCompareInstruction(CmpInst::Predicate Predicate,
   }
 
   // If the comparison is a comparison between two i1's, simplify it.
-  if (C1->getType()->isIntegerTy(1)) {
+  if (C1->getType()->isIntOrIntVectorTy(1)) {
     switch (Predicate) {
     case ICmpInst::ICMP_EQ:
-      if (isa<ConstantInt>(C2))
+      if (isa<ConstantExpr>(C1))
         return ConstantExpr::getXor(C1, ConstantExpr::getNot(C2));
       return ConstantExpr::getXor(ConstantExpr::getNot(C1), C2);
     case ICmpInst::ICMP_NE:

llvm/test/Transforms/InstSimplify/compare.ll

@@ -3465,6 +3465,26 @@ define i1 @icmp_eq_false_by_trunc(i8 %x) {
   ret i1 %cmp
 }
 
+define <vscale x 8 x i1> @icmp_ne_i1_vec_constant_expr() {
+; CHECK-LABEL: @icmp_ne_i1_vec_constant_expr(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    ret <vscale x 8 x i1> insertelement (<vscale x 8 x i1> poison, i1 true, i64 0)
+;
+entry:
+  %cmp = icmp ne <vscale x 8 x i1> insertelement (<vscale x 8 x i1> poison, i1 true, i64 0), zeroinitializer
+  ret <vscale x 8 x i1> %cmp
+}
+
+define <vscale x 8 x i1> @icmp_eq_i1_vec_constant_expr_commuted() {
+; CHECK-LABEL: @icmp_eq_i1_vec_constant_expr_commuted(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    ret <vscale x 8 x i1> xor (<vscale x 8 x i1> insertelement (<vscale x 8 x i1> poison, i1 true, i64 0), <vscale x 8 x i1> splat (i1 true))
+;
+entry:
+  %cmp = icmp eq <vscale x 8 x i1> zeroinitializer, insertelement (<vscale x 8 x i1> poison, i1 true, i64 0)
+  ret <vscale x 8 x i1> %cmp
+}
+
 declare i64 @llvm.vscale.i64()
 
 ; TODO: Add coverage for global aliases, link once, etc..