commit 2d00d0cd6e1760ea05dcbc8299ca4cf1495376d4
author Roman Lebedev <lebedev.ri@gmail.com> Mon Oct 12 11:00:52 2020 +0300
committer Copybara-Service <copybara-worker@google.com> Thu Oct 29 19:41:48 2020 -0700
tree 0417e1810db5f89bc55616c68cef965107f01b53
parent 459cb8435ed3bf3e12891aace5edbf2a74b65c7a

[SCEV] Model ptrtoint(SCEVUnknown) cast not as unknown, but as zext/trunc/self of SCEVUnknown

While we indeed can't treat them as no-ops, i believe we can/should
do better than just modelling them as `unknown`. `inttoptr` story
is complicated, but for `ptrtoint`, it seems straight-forward
to model it just as a zext-or-trunc of unknown.

This may be important now that we track towards
making inttoptr/ptrtoint casts not no-op,
and towards preventing folding them into loads/etc
(see D88979/D88789/D88788)

Reviewed By: mkazantsev

Differential Revision: https://reviews.llvm.org/D88806

GitOrigin-RevId: 1c021c64caef83cccb719c9bf0a2554faa6563af

test/Isl/CodeGen/scev_looking_through_bitcasts.ll

diff --git a/test/Isl/CodeGen/scev_looking_through_bitcasts.ll b/test/Isl/CodeGen/scev_looking_through_bitcasts.ll
index 1012e23..321e98a 100644
--- a/test/Isl/CodeGen/scev_looking_through_bitcasts.ll
+++ b/test/Isl/CodeGen/scev_looking_through_bitcasts.ll
@@ -32,6 +32,5 @@
 
 
 ; CHECK:       polly.stmt.cond.end73.i:
-; CHECK-NEXT:   %0 = bitcast %structty** %b.s2a to i8**
-; CHECK-NEXT:   store i8* undef, i8** %0
+; CHECK-NEXT:   store %structty* undef, %structty** %b.s2a
 ; CHECK-NEXT:   br label %polly.exiting