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| author | Chris Lattner <sabre@nondot.org> | 2011-02-10 07:11:16 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2011-02-10 07:11:16 +0000 |
| commit | 6cdf2ea98e9952a57768a1fcdce8850089263260 (patch) | |
| tree | 9e4aba745da2c2ade020bbd6c284111076e96177 /test/Transforms/InstCombine/icmp.ll | |
| parent | 81baf14fdfa29c22a08d609144c285169e23a247 (diff) | |
| download | llvm-6cdf2ea98e9952a57768a1fcdce8850089263260.tar.gz llvm-6cdf2ea98e9952a57768a1fcdce8850089263260.tar.bz2 llvm-6cdf2ea98e9952a57768a1fcdce8850089263260.tar.xz | |
implement the first part of PR8882: when lowering an inbounds
gep to explicit addressing, we know that none of the intermediate
computation overflows.
This could use review: it seems that the shifts certainly wouldn't
overflow, but could the intermediate adds overflow if there is a
negative index?
Previously the testcase would instcombine to:
define i1 @test(i64 %i) {
%p1.idx.mask = and i64 %i, 4611686018427387903
%cmp = icmp eq i64 %p1.idx.mask, 1000
ret i1 %cmp
}
now we get:
define i1 @test(i64 %i) {
%cmp = icmp eq i64 %i, 1000
ret i1 %cmp
}
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125271 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/Transforms/InstCombine/icmp.ll')
| -rw-r--r-- | test/Transforms/InstCombine/icmp.ll | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/test/Transforms/InstCombine/icmp.ll b/test/Transforms/InstCombine/icmp.ll index baff2cadde..72ada2476f 100644 --- a/test/Transforms/InstCombine/icmp.ll +++ b/test/Transforms/InstCombine/icmp.ll @@ -1,5 +1,8 @@ ; RUN: opt < %s -instcombine -S | FileCheck %s +target datalayout = +"e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64" + define i32 @test1(i32 %X) { entry: icmp slt i32 %X, 0 ; <i1>:0 [#uses=1] @@ -218,3 +221,16 @@ define i1 @test23(i32 %x) nounwind { %i4 = icmp eq i32 %i3, -1 ret i1 %i4 } + +@X = global [1000 x i32] zeroinitializer + +; PR8882 +; CHECK: @test24 +; CHECK: %cmp = icmp eq i64 %i, 1000 +; CHECK: ret i1 %cmp +define i1 @test24(i64 %i) { + %p1 = getelementptr inbounds i32* getelementptr inbounds ([1000 x i32]* @X, i64 0, i64 0), i64 %i + %cmp = icmp eq i32* %p1, getelementptr inbounds ([1000 x i32]* @X, i64 1, i64 0) + ret i1 %cmp +} + |