[llvm] [ConstantRange][LVI] Add initial support for `multiplyWithNoWrap` (PR #92356)

[Nikita Popov via llvm-commits]

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@@ -0,0 +1,30 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=ipsccp -S %s | FileCheck %s
+
+declare void @opaque()
+
+define i1 @range_from_mul_nuw_nsw(i32 %a) {
+; CHECK-LABEL: @range_from_mul_nuw_nsw(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[A:%.*]], 0
+; CHECK-NEXT:    br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK:       then:
+; CHECK-NEXT:    [[MUL:%.*]] = mul nuw nsw i32 [[A]], 10000
+; CHECK-NEXT:    [[ADD:%.*]] = add nsw i32 [[MUL]], -5000
+; CHECK-NEXT:    ret i1 false
+; CHECK:       else:
+; CHECK-NEXT:    call void @opaque()
+; CHECK-NEXT:    ret i1 false
+;
+entry:
+  %cmp = icmp ne i32 %a, 0
+  br i1 %cmp, label %then, label %else
+then:
+  %mul = mul nuw nsw i32 %a, 10000 ; Refined range via mul_nuw: [10000, 0)
+  %add = add nsw i32 %mul, -5000   ; Range: [5000, UINT_MAX - 5000 + 1)
+  %cond = icmp ult i32 %add, 4999
+  ret i1 %cond
+else:
+  call void @opaque()
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nikic wrote:

This call is unnecessary.

https://github.com/llvm/llvm-project/pull/92356