[llvm] [ArgPromotion] Handle pointer arguments of recursive calls (PR #78735)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,65 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S -passes=argpromotion < %s | FileCheck %s
+define internal i32 @foo(ptr %x, i32 %n, i32 %m) {
+; CHECK-LABEL: define internal i32 @foo(
+; CHECK-SAME: i32 [[X_0_VAL:%.*]], i32 [[N:%.*]], i32 [[M:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[N]], 0
+; CHECK-NEXT:    br i1 [[CMP]], label %[[COND_TRUE:.*]], label %[[COND_FALSE:.*]]
+; CHECK:       [[COND_TRUE]]:
+; CHECK-NEXT:    br label %[[RETURN:.*]]
+; CHECK:       [[COND_FALSE]]:
+; CHECK-NEXT:    [[SUBVAL:%.*]] = sub i32 [[N]], 1
+; CHECK-NEXT:    [[CALLRET:%.*]] = call i32 @foo(i32 [[X_0_VAL]], i32 [[SUBVAL]], i32 [[X_0_VAL]])
+; CHECK-NEXT:    [[SUBVAL2:%.*]] = sub i32 [[N]], 2
+; CHECK-NEXT:    [[CALLRET2:%.*]] = call i32 @foo(i32 [[X_0_VAL]], i32 [[SUBVAL2]], i32 [[M]])
+; CHECK-NEXT:    [[CMP2:%.*]] = add i32 [[CALLRET]], [[CALLRET2]]
+; CHECK-NEXT:    br label %[[RETURN]]
+; CHECK:       [[COND_NEXT:.*]]:
+; CHECK-NEXT:    br label %[[RETURN]]
+; CHECK:       [[RETURN]]:
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = phi i32 [ [[X_0_VAL]], %[[COND_TRUE]] ], [ [[CMP2]], %[[COND_FALSE]] ], [ undef, %[[COND_NEXT]] ]
+; CHECK-NEXT:    ret i32 [[RETVAL_0]]
+;
+entry:
+  %cmp = icmp ne i32 %n, 0
+  br i1 %cmp, label %cond_true, label %cond_false
+
+cond_true:                                        ; preds = %entry
+  %val = load i32, ptr %x, align 4
+  br label %return
+
+cond_false:                                       ; preds = %entry
+  %val2 = load i32, ptr %x, align 4
+  %subval = sub i32 %n, 1
+  %callret = call i32 @foo(ptr %x, i32 %subval, i32 %val2)
+  %subval2 = sub i32 %n, 2
+  %callret2 = call i32 @foo(ptr %x, i32 %subval2, i32 %m)
+  %cmp2 = add i32 %callret, %callret2
+  br label %return
+
+cond_next:                                        ; No predecessors!
+  br label %return
+
+return:                                           ; preds = %cond_next, %cond_false, %cond_true
+  %retval.0 = phi i32 [ %val, %cond_true ], [ %cmp2, %cond_false ], [ undef, %cond_next ]
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arsenm wrote:

Use poison instead of undef 

https://github.com/llvm/llvm-project/pull/78735