Mark a few Thumb instructions commutable; just happened to spot this
while experimenting. I'm reasonably sure this is correct, but please
tell me if these instructions have some strange property which makes this
change unsafe.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73746 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMInstrThumb.td b/lib/Target/ARM/ARMInstrThumb.td
index 54232f6..9297f08 100644
--- a/lib/Target/ARM/ARMInstrThumb.td
+++ b/lib/Target/ARM/ARMInstrThumb.td
@@ -277,6 +277,7 @@
//
// Add with carry
+let isCommutable = 1 in
def tADC : TIt<(outs tGPR:$dst), (ins tGPR:$lhs, tGPR:$rhs),
"adc $dst, $rhs",
[(set tGPR:$dst, (adde tGPR:$lhs, tGPR:$rhs))]>;
@@ -311,6 +312,7 @@
def tADDspi : TIt<(outs GPR:$dst), (ins GPR:$lhs, i32imm:$rhs),
"add $dst, $rhs * 4", []>;
+let isCommutable = 1 in
def tAND : TIt<(outs tGPR:$dst), (ins tGPR:$lhs, tGPR:$rhs),
"and $dst, $rhs",
[(set tGPR:$dst, (and tGPR:$lhs, tGPR:$rhs))]>;
@@ -358,6 +360,7 @@
// TODO: A7-37: CMP(3) - cmp hi regs
+let isCommutable = 1 in
def tEOR : TIt<(outs tGPR:$dst), (ins tGPR:$lhs, tGPR:$rhs),
"eor $dst, $rhs",
[(set tGPR:$dst, (xor tGPR:$lhs, tGPR:$rhs))]>;
@@ -399,6 +402,7 @@
"cpy $dst, $src\t@ hir2hir", []>;
} // neverHasSideEffects
+let isCommutable = 1 in
def tMUL : TIt<(outs tGPR:$dst), (ins tGPR:$lhs, tGPR:$rhs),
"mul $dst, $rhs",
[(set tGPR:$dst, (mul tGPR:$lhs, tGPR:$rhs))]>;
@@ -411,6 +415,7 @@
"neg $dst, $src",
[(set tGPR:$dst, (ineg tGPR:$src))]>;
+let isCommutable = 1 in
def tORR : TIt<(outs tGPR:$dst), (ins tGPR:$lhs, tGPR:$rhs),
"orr $dst, $rhs",
[(set tGPR:$dst, (or tGPR:$lhs, tGPR:$rhs))]>;
diff --git a/test/CodeGen/ARM/2009-06-18-ThumbCommuteMul.ll b/test/CodeGen/ARM/2009-06-18-ThumbCommuteMul.ll
new file mode 100644
index 0000000..9b2aba9
--- /dev/null
+++ b/test/CodeGen/ARM/2009-06-18-ThumbCommuteMul.ll
@@ -0,0 +1,8 @@
+; RUN: llvm-as < %s | llc -march=thumb | grep r0 | count 1
+
+define i32 @a(i32 %x, i32 %y) nounwind readnone {
+entry:
+ %mul = mul i32 %y, %x ; <i32> [#uses=1]
+ ret i32 %mul
+}
+