[IndVars] Add tests showing missed folding opportunity.

Author: fhahn

llvm/test/Transforms/IndVarSimplify/AArch64/fold-ext-add.ll

@@ -0,0 +1,55 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -p indvars -S %s | FileCheck %s
+
+target triple = "arm64-apple-macosx15.0.0"
+
+declare i1 @cond()
+
+define void @pred_mip_12(ptr %dst, ptr %src, i32 %n, i64 %offset) {
+; CHECK-LABEL: define void @pred_mip_12(
+; CHECK-SAME: ptr [[DST:%.*]], ptr [[SRC:%.*]], i32 [[N:%.*]], i64 [[OFFSET:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    [[SMAX:%.*]] = call i32 @llvm.smax.i32(i32 [[N]], i32 1)
+; CHECK-NEXT:    br label %[[OUTER_LOOP:.*]]
+; CHECK:       [[OUTER_LOOP_LOOPEXIT:.*]]:
+; CHECK-NEXT:    [[PTR_IV_NEXT_LCSSA:%.*]] = phi ptr [ [[PTR_IV_NEXT:%.*]], %[[INNER_LOOP:.*]] ]
+; CHECK-NEXT:    br label %[[OUTER_LOOP]]
+; CHECK:       [[OUTER_LOOP]]:
+; CHECK-NEXT:    [[OUTER_PTR:%.*]] = phi ptr [ [[SRC]], %[[ENTRY]] ], [ [[PTR_IV_NEXT_LCSSA]], %[[OUTER_LOOP_LOOPEXIT]] ]
+; CHECK-NEXT:    [[C:%.*]] = call i1 @cond()
+; CHECK-NEXT:    br i1 [[C]], label %[[INNER_LOOP_PREHEADER:.*]], label %[[EXIT:.*]]
+; CHECK:       [[INNER_LOOP_PREHEADER]]:
+; CHECK-NEXT:    br label %[[INNER_LOOP]]
+; CHECK:       [[INNER_LOOP]]:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ [[IV_NEXT:%.*]], %[[INNER_LOOP]] ], [ 0, %[[INNER_LOOP_PREHEADER]] ]
+; CHECK-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[PTR_IV_NEXT]], %[[INNER_LOOP]] ], [ [[SRC]], %[[INNER_LOOP_PREHEADER]] ]
+; CHECK-NEXT:    [[L:%.*]] = load i8, ptr [[OUTER_PTR]], align 1
+; CHECK-NEXT:    [[PTR_IV_NEXT]] = getelementptr i8, ptr [[PTR_IV]], i64 [[OFFSET]]
+; CHECK-NEXT:    store i8 [[L]], ptr [[DST]], align 2
+; CHECK-NEXT:    [[IV_NEXT]] = add nuw nsw i32 [[IV]], 1
+; CHECK-NEXT:    [[EXITCOND:%.*]] = icmp ne i32 [[IV_NEXT]], [[SMAX]]
+; CHECK-NEXT:    br i1 [[EXITCOND]], label %[[INNER_LOOP]], label %[[OUTER_LOOP_LOOPEXIT]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %outer.loop
+
+outer.loop:
+  %outer.ptr = phi ptr [ %src, %entry ], [ %ptr.iv.next, %inner.loop ]
+  %c = call i1 @cond()
+  br i1 %c, label %inner.loop, label %exit
+
+inner.loop:
+  %iv = phi i32 [ 0, %outer.loop ], [ %iv.next, %inner.loop ]
+  %ptr.iv = phi ptr [ %src, %outer.loop ], [ %ptr.iv.next, %inner.loop ]
+  %l = load i8, ptr %outer.ptr, align 1
+  %ptr.iv.next = getelementptr i8, ptr %ptr.iv, i64 %offset
+  store i8 %l, ptr %dst, align 2
+  %iv.next = add i32 %iv, 1
+  %ec = icmp slt i32 %iv.next, %n
+  br i1 %ec, label %inner.loop, label %outer.loop
+
+exit:
+  ret void
+}