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| author | Zhan Jun Liau <zhanjunl@ca.ibm.com> | 2016-06-27 15:55:30 +0000 |
|---|---|---|
| committer | Zhan Jun Liau <zhanjunl@ca.ibm.com> | 2016-06-27 15:55:30 +0000 |
| commit | 4f130b4410b2662e9adb1947cd402d9593409c21 (patch) | |
| tree | 5d3420d855e7dbf75b02fdf7a984db6348731b34 | |
| parent | 02478f416639e1e322df34c139cd90874dcfb2c1 (diff) | |
| download | bcm5719-llvm-4f130b4410b2662e9adb1947cd402d9593409c21.tar.gz bcm5719-llvm-4f130b4410b2662e9adb1947cd402d9593409c21.zip | |
[SystemZ] Avoid generating 2 XOR instructions for (and (xor x, -1), y)
Summary:
Created a pattern to match 64-bit mode (and (xor x, -1), y)
to a shorter sequence of instructions.
Before the change, the canonical form is translated to:
xihf %r3, 4294967295
xilf %r3, 4294967295
ngr %r2, %r3
After the change, the canonical form is translated to:
ngr %r3, %r2
xgr %r2, %r3
Reviewers: zhanjunl, uweigand
Subscribers: llvm-commits
Author: assem
Committing on behalf of Assem.
Differential Revision: http://reviews.llvm.org/D21693
llvm-svn: 273887
| -rw-r--r-- | llvm/lib/Target/SystemZ/SystemZInstrInfo.td | 5 | ||||
| -rw-r--r-- | llvm/test/CodeGen/SystemZ/and-xor-01.ll | 14 |
2 files changed, 19 insertions, 0 deletions
diff --git a/llvm/lib/Target/SystemZ/SystemZInstrInfo.td b/llvm/lib/Target/SystemZ/SystemZInstrInfo.td index 77a9fdd4add..7a7a3e30863 100644 --- a/llvm/lib/Target/SystemZ/SystemZInstrInfo.td +++ b/llvm/lib/Target/SystemZ/SystemZInstrInfo.td @@ -1680,6 +1680,11 @@ def : Pat<(sra (shl (i64 (anyext (i32 (z_select_ccmask 1, 0, imm32zx4:$valid, (i32 63)), (Select64 (LGHI -1), (LGHI 0), imm32zx4:$valid, imm32zx4:$cc)>; +// Avoid generating 2 XOR instructions. (xor (and x, y), y) is +// equivalent to (and (xor x, -1), y) +def : Pat<(and (xor GR64:$x, (i64 -1)), GR64:$y), + (XGR GR64:$y, (NGR GR64:$y, GR64:$x))>; + // Peepholes for turning scalar operations into block operations. defm : BlockLoadStore<anyextloadi8, i32, MVCSequence, NCSequence, OCSequence, XCSequence, 1>; diff --git a/llvm/test/CodeGen/SystemZ/and-xor-01.ll b/llvm/test/CodeGen/SystemZ/and-xor-01.ll new file mode 100644 index 00000000000..f29c7d576d9 --- /dev/null +++ b/llvm/test/CodeGen/SystemZ/and-xor-01.ll @@ -0,0 +1,14 @@ +; Testing peephole for generating shorter code for (and (xor b, -1), a) +; +; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s + +define i64 @f1(i64 %a, i64 %b) { +; CHECK-LABEL: f1: +; CHECK: ngr %r3, %r2 +; CHECK: xgr %r2, %r3 +; CHECK: br %r14 + %neg = xor i64 %b, -1 + %and = and i64 %neg, %a + ret i64 %and +} + |
