[IR] Value: add replaceUsesWithIf() utility

Summary:
While there is always a `Value::replaceAllUsesWith()`,
sometimes the replacement needs to be conditional.

I have only cleaned a few cases where `replaceUsesWithIf()`
could be used, to both add test coverage,
and show that it is actually useful.

Reviewers: jdoerfert, spatel, RKSimon, craig.topper

Reviewed By: jdoerfert

Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, aheejin, george.burgess.iv, asbirlea, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65528

llvm-svn: 367548

1 files changed, 2 insertions, 5 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyOptimizeReturned.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyOptimizeReturned.cpp
index d20352259e0..9b60596e42b 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyOptimizeReturned.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyOptimizeReturned.cpp
@@ -64,11 +64,8 @@ void OptimizeReturned::visitCallSite(CallSite CS) {
       if (isa<Constant>(Arg))
         continue;
       // Like replaceDominatedUsesWith but using Instruction/Use dominance.
-      for (auto UI = Arg->use_begin(), UE = Arg->use_end(); UI != UE;) {
-        Use &U = *UI++;
-        if (DT->dominates(Inst, U))
-          U.set(Inst);
-      }
+      Arg->replaceUsesWithIf(Inst,
+                             [&](Use &U) { return DT->dominates(Inst, U); });
     }
 }