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author | Florian Hahn <flo@fhahn.com> | 2024-03-12 09:47:42 +0000 |
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committer | Tom Stellard <tstellar@redhat.com> | 2024-03-13 11:01:14 -0700 |
commit | 7b61ddefc28a2c88be3a754ceee7bace98e3b187 (patch) | |
tree | a7a9bbf06b7ae7211db6ff461a12a7f7b2941d18 | |
parent | 25a989ce8bf35ccda064d956305f920bf711a7de (diff) | |
download | llvm-7b61ddefc28a2c88be3a754ceee7bace98e3b187.zip llvm-7b61ddefc28a2c88be3a754ceee7bace98e3b187.tar.gz llvm-7b61ddefc28a2c88be3a754ceee7bace98e3b187.tar.bz2 |
[ArgPromotion] Remove incorrect TranspBlocks set for loads. (#84835)
The TranspBlocks set was used to cache aliasing decision for all
processed loads in the parent loop. This is incorrect, because each load
can access a different location, which means one load not being modified
in a block doesn't translate to another load not being modified in the
same block.
All loads access the same underlying object, so we could perhaps use a
location without size for all loads and retain the cache, but that would
mean we loose precision.
For now, just drop the cache.
Fixes https://github.com/llvm/llvm-project/issues/84807
PR: https://github.com/llvm/llvm-project/pull/84835
(cherry picked from commit bba4a1daff6ee09941f1369a4e56b4af95efdc5c)
-rw-r--r-- | llvm/lib/Transforms/IPO/ArgumentPromotion.cpp | 6 | ||||
-rw-r--r-- | llvm/test/Transforms/ArgumentPromotion/aliasing-and-non-aliasing-loads-with-clobber.ll | 14 |
2 files changed, 8 insertions, 12 deletions
diff --git a/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp b/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp index 8058282..062a3d3 100644 --- a/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp +++ b/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp @@ -652,10 +652,6 @@ static bool findArgParts(Argument *Arg, const DataLayout &DL, AAResults &AAR, // check to see if the pointer is guaranteed to not be modified from entry of // the function to each of the load instructions. - // Because there could be several/many load instructions, remember which - // blocks we know to be transparent to the load. - df_iterator_default_set<BasicBlock *, 16> TranspBlocks; - for (LoadInst *Load : Loads) { // Check to see if the load is invalidated from the start of the block to // the load itself. @@ -669,7 +665,7 @@ static bool findArgParts(Argument *Arg, const DataLayout &DL, AAResults &AAR, // To do this, we perform a depth first search on the inverse CFG from the // loading block. for (BasicBlock *P : predecessors(BB)) { - for (BasicBlock *TranspBB : inverse_depth_first_ext(P, TranspBlocks)) + for (BasicBlock *TranspBB : inverse_depth_first(P)) if (AAR.canBasicBlockModify(*TranspBB, Loc)) return false; } diff --git a/llvm/test/Transforms/ArgumentPromotion/aliasing-and-non-aliasing-loads-with-clobber.ll b/llvm/test/Transforms/ArgumentPromotion/aliasing-and-non-aliasing-loads-with-clobber.ll index 69385a7..1e1669b 100644 --- a/llvm/test/Transforms/ArgumentPromotion/aliasing-and-non-aliasing-loads-with-clobber.ll +++ b/llvm/test/Transforms/ArgumentPromotion/aliasing-and-non-aliasing-loads-with-clobber.ll @@ -7,17 +7,14 @@ target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80: ; Test case for https://github.com/llvm/llvm-project/issues/84807. -; FIXME: Currently the loads from @callee are moved to @caller, even though -; the store in %then may aliases to load from %q. +; Make sure the loads from @callee are not moved to @caller, as the store +; in %then may aliases to load from %q. define i32 @caller1(i1 %c) { ; CHECK-LABEL: define i32 @caller1( ; CHECK-SAME: i1 [[C:%.*]]) { ; CHECK-NEXT: entry: -; CHECK-NEXT: [[F_VAL:%.*]] = load i16, ptr @f, align 8 -; CHECK-NEXT: [[TMP0:%.*]] = getelementptr i8, ptr @f, i64 8 -; CHECK-NEXT: [[F_VAL1:%.*]] = load i64, ptr [[TMP0]], align 8 -; CHECK-NEXT: call void @callee1(i16 [[F_VAL]], i64 [[F_VAL1]], i1 [[C]]) +; CHECK-NEXT: call void @callee1(ptr noundef nonnull @f, i1 [[C]]) ; CHECK-NEXT: ret i32 0 ; entry: @@ -27,13 +24,16 @@ entry: define internal void @callee1(ptr nocapture noundef readonly %q, i1 %c) { ; CHECK-LABEL: define internal void @callee1( -; CHECK-SAME: i16 [[Q_0_VAL:%.*]], i64 [[Q_8_VAL:%.*]], i1 [[C:%.*]]) { +; CHECK-SAME: ptr nocapture noundef readonly [[Q:%.*]], i1 [[C:%.*]]) { ; CHECK-NEXT: entry: ; CHECK-NEXT: br i1 [[C]], label [[THEN:%.*]], label [[EXIT:%.*]] ; CHECK: then: ; CHECK-NEXT: store i16 123, ptr @f, align 8 ; CHECK-NEXT: br label [[EXIT]] ; CHECK: exit: +; CHECK-NEXT: [[Q_0_VAL:%.*]] = load i16, ptr [[Q]], align 8 +; CHECK-NEXT: [[GEP_8:%.*]] = getelementptr inbounds i8, ptr [[Q]], i64 8 +; CHECK-NEXT: [[Q_8_VAL:%.*]] = load i64, ptr [[GEP_8]], align 8 ; CHECK-NEXT: call void @use(i16 [[Q_0_VAL]], i64 [[Q_8_VAL]]) ; CHECK-NEXT: ret void ; |