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| author | Kyle Butt <kyle+llvm@iteratee.net> | 2016-08-24 21:34:24 +0000 |
|---|---|---|
| committer | Kyle Butt <kyle+llvm@iteratee.net> | 2016-08-24 21:34:24 +0000 |
| commit | 6262ca3448e2698e6c65d911f13fc22e4cc40be8 (patch) | |
| tree | 4e9499d7edd305d69447bc6f36396b627ffaefae /llvm/test/CodeGen/ARM | |
| parent | bcc77b6249a6f193f7322dbb3fdf77482d67bbee (diff) | |
| download | bcm5719-llvm-6262ca3448e2698e6c65d911f13fc22e4cc40be8.tar.gz bcm5719-llvm-6262ca3448e2698e6c65d911f13fc22e4cc40be8.zip | |
IfConversion: Rescan diamonds.
The cost of predicating a diamond is only the instructions that are not shared
between the two branches. Additionally If a predicate clobbering instruction
occurs in the shared portion of the branches (e.g. a cond move), it may still
be possible to if convert the sub-cfg. This change handles these two facts by
rescanning the non-shared portion of a diamond sub-cfg to recalculate both the
predication cost and whether both blocks are pred-clobbering.
Fixed 2 bugs before recommitting. Branch instructions must be compared and found
identical before diamond conversion. Also, predicate-clobbering instructions in
the shared prefix disqualifies a potential diamond conversion. Includes tests
for both.
llvm-svn: 279670
Diffstat (limited to 'llvm/test/CodeGen/ARM')
| -rw-r--r-- | llvm/test/CodeGen/ARM/indirectbr-3.ll | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/llvm/test/CodeGen/ARM/indirectbr-3.ll b/llvm/test/CodeGen/ARM/indirectbr-3.ll index 291fedb8110..da383989332 100644 --- a/llvm/test/CodeGen/ARM/indirectbr-3.ll +++ b/llvm/test/CodeGen/ARM/indirectbr-3.ll @@ -1,4 +1,4 @@ -; RUN: llc < %s -mtriple=thumbv7-apple-ios -arm-atomic-cfg-tidy=0 | FileCheck %s +; RUN: llc < %s -mtriple=thumbv7-apple-ios -arm-atomic-cfg-tidy=0 -stats 2>&1 | FileCheck %s ; If ARMBaseInstrInfo::AnalyzeBlocks returns the wrong value, which was possible ; for blocks with indirect branches, the IfConverter could end up deleting @@ -9,9 +9,17 @@ define i32 @preserve_blocks(i32 %x) { ; preserve_blocks: ; CHECK: Block address taken -; CHECK: movs r0, #2 ; CHECK: movs r0, #1 +; CHECK: Block address taken +; CHECK: movs r0, #2 ; CHECK-NOT: Address of block that was removed by CodeGen + +; Separate bug. There are no valid diamonds to if-convert in this file. +; There was a bug in the if-conversion code that would if-convert a false +; diamond where one side had a return and the other had an indirect branch. +; Make sure no diamond conversions occurred while compiling this file. +; CHECK: Statistics Collected +; CHECK-NOT: 1 ifcvt - Number of diamond if-conversions performed entry: %c2 = icmp slt i32 %x, 3 %blockaddr = select i1 %c2, i8* blockaddress(@preserve_blocks, %ibt1), i8* blockaddress(@preserve_blocks, %ibt2) |
