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llvm-project/llvm/test/CodeGen/PowerPC/early-ret2.ll

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Add CR-bit tracking to the PowerPC backend for i1 values This change enables tracking i1 values in the PowerPC backend using the condition register bits. These bits can be treated on PowerPC as separate registers; individual bit operations (and, or, xor, etc.) are supported. Tracking booleans in CR bits has several advantages: - Reduction in register pressure (because we no longer need GPRs to store boolean values). - Logical operations on booleans can be handled more efficiently; we used to have to move all results from comparisons into GPRs, perform promoted logical operations in GPRs, and then move the result back into condition register bits to be used by conditional branches. This can be very inefficient, because the throughput of these CR <-> GPR moves have high latency and low throughput (especially when other associated instructions are accounted for). - On the POWER7 and similar cores, we can increase total throughput by using the CR bits. CR bit operations have a dedicated functional unit. Most of this is more-or-less mechanical: Adjustments were needed in the calling-convention code, support was added for spilling/restoring individual condition-register bits, and conditional branch instruction definitions taking specific CR bits were added (plus patterns and code for generating bit-level operations). This is enabled by default when running at -O2 and higher. For -O0 and -O1, where the ability to debug is more important, this feature is disabled by default. Individual CR bits do not have assigned DWARF register numbers, and storing values in CR bits makes them invisible to the debugger. It is critical, however, that we don't move i1 values that have been promoted to larger values (such as those passed as function arguments) into bit registers only to quickly turn around and move the values back into GPRs (such as happens when values are returned by functions). A pair of target-specific DAG combines are added to remove the trunc/extends in: trunc(binary-ops(binary-ops(zext(x), zext(y)), ...) and: zext(binary-ops(binary-ops(trunc(x), trunc(y)), ...) In short, we only want to use CR bits where some of the i1 values come from comparisons or are used by conditional branches or selects. To put it another way, if we can do the entire i1 computation in GPRs, then we probably should (on the POWER7, the GPR-operation throughput is higher, and for all cores, the CR <-> GPR moves are expensive). POWER7 test-suite performance results (from 10 runs in each configuration): SingleSource/Benchmarks/Misc/mandel-2: 35% speedup MultiSource/Benchmarks/Prolangs-C++/city/city: 21% speedup MultiSource/Benchmarks/MiBench/automotive-susan: 23% speedup SingleSource/Benchmarks/CoyoteBench/huffbench: 13% speedup SingleSource/Benchmarks/Misc-C++/Large/sphereflake: 13% speedup SingleSource/Benchmarks/Misc-C++/mandel-text: 10% speedup SingleSource/Benchmarks/Misc-C++-EH/spirit: 10% slowdown MultiSource/Applications/lemon/lemon: 8% slowdown llvm-svn: 202451
2014-02-28 08:27:01 +08:00
; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu -mcpu=pwr7 -mattr=-crbits | FileCheck %s
; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu -mcpu=pwr7 | FileCheck %s -check-prefix=CHECK-CRB
Allow PPC B and BLR to be if-converted into some predicated forms This enables us to form predicated branches (which are the same conditional branches we had before) and also a larger set of predicated returns (including instructions like bdnzlr which is a conditional return and loop-counter decrement all in one). At the moment, if conversion does not capture all possible opportunities. A simple example is provided in early-ret2.ll, where if conversion forms one predicated return, and then the PPCEarlyReturn pass picks up the other one. So, at least for now, we'll keep both mechanisms. llvm-svn: 179134
2013-04-10 06:58:37 +08:00
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-f128:128:128-v128:128:128-n32:64"
target triple = "powerpc64-unknown-linux-gnu"
define void @_Z8example3iPiS_() #0 {
entry:
br i1 undef, label %while.end, label %while.body.lr.ph
while.body.lr.ph: ; preds = %entry
br i1 undef, label %while.end, label %while.body
while.body: ; preds = %while.body, %while.body.lr.ph
Rename loop unrolling and loop vectorizer metadata to have a common prefix. [LLVM part] These patches rename the loop unrolling and loop vectorizer metadata such that they have a common 'llvm.loop.' prefix. Metadata name changes: llvm.vectorizer.* => llvm.loop.vectorizer.* llvm.loopunroll.* => llvm.loop.unroll.* This was a suggestion from an earlier review (http://reviews.llvm.org/D4090) which added the loop unrolling metadata. Patch by Mark Heffernan. llvm-svn: 211710
2014-06-25 23:41:00 +08:00
br i1 false, label %while.end, label %while.body, !llvm.loop.vectorize.already_vectorized !0
Allow PPC B and BLR to be if-converted into some predicated forms This enables us to form predicated branches (which are the same conditional branches we had before) and also a larger set of predicated returns (including instructions like bdnzlr which is a conditional return and loop-counter decrement all in one). At the moment, if conversion does not capture all possible opportunities. A simple example is provided in early-ret2.ll, where if conversion forms one predicated return, and then the PPCEarlyReturn pass picks up the other one. So, at least for now, we'll keep both mechanisms. llvm-svn: 179134
2013-04-10 06:58:37 +08:00
while.end: ; preds = %while.body, %while.body.lr.ph, %entry
ret void
; CHECK: @_Z8example3iPiS_
; CHECK: bnelr
Add CR-bit tracking to the PowerPC backend for i1 values This change enables tracking i1 values in the PowerPC backend using the condition register bits. These bits can be treated on PowerPC as separate registers; individual bit operations (and, or, xor, etc.) are supported. Tracking booleans in CR bits has several advantages: - Reduction in register pressure (because we no longer need GPRs to store boolean values). - Logical operations on booleans can be handled more efficiently; we used to have to move all results from comparisons into GPRs, perform promoted logical operations in GPRs, and then move the result back into condition register bits to be used by conditional branches. This can be very inefficient, because the throughput of these CR <-> GPR moves have high latency and low throughput (especially when other associated instructions are accounted for). - On the POWER7 and similar cores, we can increase total throughput by using the CR bits. CR bit operations have a dedicated functional unit. Most of this is more-or-less mechanical: Adjustments were needed in the calling-convention code, support was added for spilling/restoring individual condition-register bits, and conditional branch instruction definitions taking specific CR bits were added (plus patterns and code for generating bit-level operations). This is enabled by default when running at -O2 and higher. For -O0 and -O1, where the ability to debug is more important, this feature is disabled by default. Individual CR bits do not have assigned DWARF register numbers, and storing values in CR bits makes them invisible to the debugger. It is critical, however, that we don't move i1 values that have been promoted to larger values (such as those passed as function arguments) into bit registers only to quickly turn around and move the values back into GPRs (such as happens when values are returned by functions). A pair of target-specific DAG combines are added to remove the trunc/extends in: trunc(binary-ops(binary-ops(zext(x), zext(y)), ...) and: zext(binary-ops(binary-ops(trunc(x), trunc(y)), ...) In short, we only want to use CR bits where some of the i1 values come from comparisons or are used by conditional branches or selects. To put it another way, if we can do the entire i1 computation in GPRs, then we probably should (on the POWER7, the GPR-operation throughput is higher, and for all cores, the CR <-> GPR moves are expensive). POWER7 test-suite performance results (from 10 runs in each configuration): SingleSource/Benchmarks/Misc/mandel-2: 35% speedup MultiSource/Benchmarks/Prolangs-C++/city/city: 21% speedup MultiSource/Benchmarks/MiBench/automotive-susan: 23% speedup SingleSource/Benchmarks/CoyoteBench/huffbench: 13% speedup SingleSource/Benchmarks/Misc-C++/Large/sphereflake: 13% speedup SingleSource/Benchmarks/Misc-C++/mandel-text: 10% speedup SingleSource/Benchmarks/Misc-C++-EH/spirit: 10% slowdown MultiSource/Applications/lemon/lemon: 8% slowdown llvm-svn: 202451
2014-02-28 08:27:01 +08:00
; CHECK-CRB: @_Z8example3iPiS_
; CHECK-CRB: bclr 12,
Allow PPC B and BLR to be if-converted into some predicated forms This enables us to form predicated branches (which are the same conditional branches we had before) and also a larger set of predicated returns (including instructions like bdnzlr which is a conditional return and loop-counter decrement all in one). At the moment, if conversion does not capture all possible opportunities. A simple example is provided in early-ret2.ll, where if conversion forms one predicated return, and then the PPCEarlyReturn pass picks up the other one. So, at least for now, we'll keep both mechanisms. llvm-svn: 179134
2013-04-10 06:58:37 +08:00
}
attributes #0 = { noinline nounwind }
IR: Make metadata typeless in assembly Now that `Metadata` is typeless, reflect that in the assembly. These are the matching assembly changes for the metadata/value split in r223802. - Only use the `metadata` type when referencing metadata from a call intrinsic -- i.e., only when it's used as a `Value`. - Stop pretending that `ValueAsMetadata` is wrapped in an `MDNode` when referencing it from call intrinsics. So, assembly like this: define @foo(i32 %v) { call void @llvm.foo(metadata !{i32 %v}, metadata !0) call void @llvm.foo(metadata !{i32 7}, metadata !0) call void @llvm.foo(metadata !1, metadata !0) call void @llvm.foo(metadata !3, metadata !0) call void @llvm.foo(metadata !{metadata !3}, metadata !0) ret void, !bar !2 } !0 = metadata !{metadata !2} !1 = metadata !{i32* @global} !2 = metadata !{metadata !3} !3 = metadata !{} turns into this: define @foo(i32 %v) { call void @llvm.foo(metadata i32 %v, metadata !0) call void @llvm.foo(metadata i32 7, metadata !0) call void @llvm.foo(metadata i32* @global, metadata !0) call void @llvm.foo(metadata !3, metadata !0) call void @llvm.foo(metadata !{!3}, metadata !0) ret void, !bar !2 } !0 = !{!2} !1 = !{i32* @global} !2 = !{!3} !3 = !{} I wrote an upgrade script that handled almost all of the tests in llvm and many of the tests in cfe (even handling many `CHECK` lines). I've attached it (or will attach it in a moment if you're speedy) to PR21532 to help everyone update their out-of-tree testcases. This is part of PR21532. llvm-svn: 224257
2014-12-16 03:07:53 +08:00
!0 = !{}
Allow PPC B and BLR to be if-converted into some predicated forms This enables us to form predicated branches (which are the same conditional branches we had before) and also a larger set of predicated returns (including instructions like bdnzlr which is a conditional return and loop-counter decrement all in one). At the moment, if conversion does not capture all possible opportunities. A simple example is provided in early-ret2.ll, where if conversion forms one predicated return, and then the PPCEarlyReturn pass picks up the other one. So, at least for now, we'll keep both mechanisms. llvm-svn: 179134
2013-04-10 06:58:37 +08:00