[llvm] [MergeFunc] Handle ConstantRange attributes. (PR #88584)

[Andreas Jonson via llvm-commits]

https://github.com/andjo403 created https://github.com/llvm/llvm-project/pull/88584

It is possible to update [AttributeImpl::operator<](https://github.com/andjo403/llvm-project/blob/a9da350aadfb5c86d36ae18398471558b22c1309/llvm/lib/IR/Attributes.cpp#L744) instead but feels strange to say that a range is less then an other range.

CC @nikic 

>From a9da350aadfb5c86d36ae18398471558b22c1309 Mon Sep 17 00:00:00 2001
From: Andreas Jonson <andjo403 at hotmail.com>
Date: Fri, 12 Apr 2024 23:35:47 +0200
Subject: [PATCH] [MergeFunc]  Handle ConstantRange attributes.

---
 .../Transforms/Utils/FunctionComparator.cpp   |   8 ++
 .../call-and-invoke-with-ranges-attr.ll       | 111 ++++++++++++++++++
 2 files changed, 119 insertions(+)
 create mode 100644 llvm/test/Transforms/MergeFunc/call-and-invoke-with-ranges-attr.ll

diff --git a/llvm/lib/Transforms/Utils/FunctionComparator.cpp b/llvm/lib/Transforms/Utils/FunctionComparator.cpp
index 8cfb8ed07d240e..0c520ec7c5d2dd 100644
--- a/llvm/lib/Transforms/Utils/FunctionComparator.cpp
+++ b/llvm/lib/Transforms/Utils/FunctionComparator.cpp
@@ -143,6 +143,14 @@ int FunctionComparator::cmpAttrs(const AttributeList L,
         if (int Res = cmpNumbers((uint64_t)TyL, (uint64_t)TyR))
           return Res;
         continue;
+      } else if (LA.isConstantRangeAttribute() &&
+                 RA.isConstantRangeAttribute()) {
+        ConstantRange LCR = LA.getRange();
+        ConstantRange RCR = RA.getRange();
+        if (int Res = cmpAPInts(LCR.getLower(), RCR.getLower()))
+          return Res;
+        if (int Res = cmpAPInts(LCR.getUpper(), RCR.getUpper()))
+          return Res;
       }
       if (LA < RA)
         return -1;
diff --git a/llvm/test/Transforms/MergeFunc/call-and-invoke-with-ranges-attr.ll b/llvm/test/Transforms/MergeFunc/call-and-invoke-with-ranges-attr.ll
new file mode 100644
index 00000000000000..e5d62319bf9db7
--- /dev/null
+++ b/llvm/test/Transforms/MergeFunc/call-and-invoke-with-ranges-attr.ll
@@ -0,0 +1,111 @@
+; RUN: opt -passes=mergefunc -S < %s | FileCheck %s
+
+define i8 @call_with_range_attr(i8 range(i8 0, 2) %v) {
+  %out = call i8 @dummy2(i8 %v)
+  ret i8 %out
+}
+
+define i8 @call_no_range_attr(i8 %v) {
+; CHECK-LABEL: @call_no_range_attr
+; CHECK-NEXT: %out = call i8 @dummy2(i8 %v)
+; CHECK-NEXT: ret i8 %out
+  %out = call i8 @dummy2(i8 %v)
+  ret i8 %out
+}
+
+define i8 @call_different_range_attr(i8 range(i8 5, 7) %v) {
+; CHECK-LABEL: @call_different_range_attr
+; CHECK-NEXT: %out = call i8 @dummy2(i8 %v)
+; CHECK-NEXT: ret i8 %out
+  %out = call i8 @dummy2(i8 %v)
+  ret i8 %out
+}
+
+define i8 @call_with_range() {
+  %out = call range(i8 0, 2) i8 @dummy()
+  ret i8 %out
+}
+
+define i8 @call_no_range() {
+; CHECK-LABEL: @call_no_range
+; CHECK-NEXT: %out = call i8 @dummy()
+; CHECK-NEXT: ret i8 %out
+  %out = call i8 @dummy()
+  ret i8 %out
+}
+
+define i8 @call_different_range() {
+; CHECK-LABEL: @call_different_range
+; CHECK-NEXT: %out = call range(i8 5, 7) i8 @dummy()
+; CHECK-NEXT: ret i8 %out
+  %out = call range(i8 5, 7) i8 @dummy()
+  ret i8 %out
+}
+
+define i8 @invoke_with_range() personality ptr undef {
+  %out = invoke range(i8 0, 2) i8 @dummy() to label %next unwind label %lpad
+
+next:
+  ret i8 %out
+
+lpad:
+  %pad = landingpad { ptr, i32 } cleanup
+  resume { ptr, i32 } zeroinitializer
+}
+
+define i8 @invoke_no_range() personality ptr undef {
+; CHECK-LABEL: @invoke_no_range()
+; CHECK-NEXT: invoke i8 @dummy
+  %out = invoke i8 @dummy() to label %next unwind label %lpad
+
+next:
+  ret i8 %out
+
+lpad:
+  %pad = landingpad { ptr, i32 } cleanup
+  resume { ptr, i32 } zeroinitializer
+}
+
+define i8 @invoke_different_range() personality ptr undef {
+; CHECK-LABEL: @invoke_different_range()
+; CHECK-NEXT: invoke range(i8 5, 7) i8 @dummy
+  %out = invoke range(i8 5, 7) i8 @dummy() to label %next unwind label %lpad
+
+next:
+  ret i8 %out
+
+lpad:
+  %pad = landingpad { ptr, i32 } cleanup
+  resume { ptr, i32 } zeroinitializer
+}
+
+define i8 @invoke_with_same_range() personality ptr undef {
+; CHECK-LABEL: @invoke_with_same_range()
+; CHECK: tail call i8 @invoke_with_range()
+  %out = invoke range(i8 0, 2) i8 @dummy() to label %next unwind label %lpad
+
+next:
+  ret i8 %out
+
+lpad:
+  %pad = landingpad { ptr, i32 } cleanup
+  resume { ptr, i32 } zeroinitializer
+}
+
+define i8 @call_with_same_range() {
+; CHECK-LABEL: @call_with_same_range
+; CHECK: tail call i8 @call_with_range
+  %out = call range(i8 0, 2) i8 @dummy()
+  ret i8 %out
+}
+
+define i8 @call_with_same_range_attr(i8 range(i8 0, 2) %v) {
+; CHECK-LABEL: @call_with_same_range_attr
+; CHECK: tail call i8 @call_with_range_attr
+  %out = call i8 @dummy2(i8 %v)
+  ret i8 %out
+}
+
+declare i8 @dummy();
+declare i8 @dummy2(i8);
+declare i32 @__gxx_personality_v0(...)