[PATCH] D19526: Allow unsigned comparisons

[Michael Kruse via llvm-commits]

Meinersbur accepted this revision.
This revision is now accepted and ready to land.

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Comment at: lib/Analysis/ScopInfo.cpp:1323-1326
@@ +1322,6 @@
+      auto *BB = Stmt.getEntryBlock();
+      S.recordAssumption(UNSIGNED, isl_pw_aff_nonneg_set(isl_pw_aff_copy(LHS)),
+                         TI->getDebugLoc(), AS_ASSUMPTION, BB);
+      S.recordAssumption(UNSIGNED, isl_pw_aff_nonneg_set(isl_pw_aff_copy(RHS)),
+                         TI->getDebugLoc(), AS_ASSUMPTION, BB);
+    }
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I assume that RTCs checks will always be signed therefor this will check whether the MSB is not 1. Could you add a comment for that?

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Comment at: test/ScopInfo/simple_loop_unsigned.ll:3-7
@@ +2,7 @@
+
+; void f(int a[], int N) {
+;   int i;
+;   for (i = 0; i < N; ++i)
+;     a[i] = i;
+; }
+
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This has no unsigned comparison. Can you make it represent the IR below? Eg.

    for (i = 0; (uint64_t)i < (uint64_t)N; ++i)

%i is of type i64, so I suggest to declare `i` as `int64_t`

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Comment at: test/ScopInfo/simple_loop_unsigned.ll:13
@@ +12,3 @@
+; CHECK:      Arrays {
+; CHECK-NEXT:     i64 MemRef_a[*]; // Element size 8
+; CHECK-NEXT: }
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Why is this significant for the test case?

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Comment at: test/ScopInfo/simple_loop_unsigned_2.ll:36
@@ +35,3 @@
+  store i64 %i, i64* %scevgep
+  %i.dec = add nsw i64 %i, -1
+  %exitcond = icmp ugt i64 %i.dec, 0
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Since `i` is unsigned, why does it have a nsw flag?


http://reviews.llvm.org/D19526