[PowerPC] Eliminate sign- and zero-extensions if already sign- or zero-extended

This patch enables redundant sign- and zero-extension elimination in PowerPC MI Peephole pass.
If the input value of a sign- or zero-extension is known to be already sign- or zero-extended, the operation is redundant and can be eliminated.
One common case is sign-extensions for a method parameter or for a method return value; they must be sign- or zero-extended as defined in PPC ELF ABI. 
For example of the following simple code, two extsw instructions are generated before the invocation of int_func and before the return. With this patch, both extsw are eliminated.

void int_func(int);
void ii_test(int a) {
    if (a & 1) return int_func(a);
}

Such redundant sign- or zero-extensions are quite common in many programs; e.g. I observed about 60,000 occurrences of the elimination while compiling the LLVM+CLANG.

Differential Revision: https://reviews.llvm.org/D31319



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315888 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 4 insertions, 62 deletions

diff --git a/test/CodeGen/PowerPC/expand-isel.ll b/test/CodeGen/PowerPC/expand-isel.ll
index 84d17baf13a..76479705f02 100644
--- a/test/CodeGen/PowerPC/expand-isel.ll
+++ b/test/CodeGen/PowerPC/expand-isel.ll
@@ -215,9 +215,7 @@ cleanup:
 ; CHECK-LABEL: @testComplexISEL
 ; CHECK-DAG: [[LI:r[0-9]+]], 1
 ; CHECK-DAG: cmplwi [[LD:r[0-9]+]], 0
-; CHECK: beq cr0, [[EQ:.LBB[0-9_]+]]
-; CHECK: blr
-; CHECK: [[EQ]]
+; CHECK: bnelr cr0
 ; CHECK: xor [[XOR:r[0-9]+]]
 ; CHECK: cntlzd [[CZ:r[0-9]+]], [[XOR]]
 ; CHECK: rldicl [[SH:r[0-9]+]], [[CZ]], 58, 63
diff --git a/test/CodeGen/PowerPC/memCmpUsedInZeroEqualityComparison.ll b/test/CodeGen/PowerPC/memCmpUsedInZeroEqualityComparison.ll
index cc850273202..27e9c1b8819 100644
--- a/test/CodeGen/PowerPC/memCmpUsedInZeroEqualityComparison.ll
+++ b/test/CodeGen/PowerPC/memCmpUsedInZeroEqualityComparison.ll
@@ -45,13 +45,9 @@ define signext i32 @zeroEqualityTest01(i8* %x, i8* %y) {
 ; CHECK-NEXT:    ld 4, 8(4)
 ; CHECK-NEXT:    cmpld 3, 4
 ; CHECK-NEXT:    li 3, 0
-; CHECK-NEXT:    beq 0, .LBB1_3
+; CHECK-NEXT:    beqlr 0
 ; CHECK-NEXT:  .LBB1_2: # %res_block
 ; CHECK-NEXT:    li 3, 1
-; CHECK-NEXT:    clrldi 3, 3, 32
-; CHECK-NEXT:    blr
-; CHECK-NEXT:  .LBB1_3: # %endblock
-; CHECK-NEXT:    clrldi 3, 3, 32
 ; CHECK-NEXT:    blr
   %call = tail call signext i32 @memcmp(i8* %x, i8* %y, i64 16)
   %not.tobool = icmp ne i32 %call, 0
@@ -77,13 +73,9 @@ define signext i32 @zeroEqualityTest03(i8* %x, i8* %y) {
 ; CHECK-NEXT:    lbz 4, 6(4)
 ; CHECK-NEXT:    cmplw 3, 4
 ; CHECK-NEXT:    li 3, 0
-; CHECK-NEXT:    beq 0, .LBB2_4
+; CHECK-NEXT:    beqlr 0
 ; CHECK-NEXT:  .LBB2_3: # %res_block
 ; CHECK-NEXT:    li 3, 1
-; CHECK-NEXT:    clrldi 3, 3, 32
-; CHECK-NEXT:    blr
-; CHECK-NEXT:  .LBB2_4: # %endblock
-; CHECK-NEXT:    clrldi 3, 3, 32
 ; CHECK-NEXT:    blr
   %call = tail call signext i32 @memcmp(i8* %x, i8* %y, i64 7)
   %not.lnot = icmp ne i32 %call, 0
diff --git a/test/CodeGen/PowerPC/p8-scalar_vector_conversions.ll b/test/CodeGen/PowerPC/p8-scalar_vector_conversions.ll
index f399b2584d0..3c705bb3e6c 100644
--- a/test/CodeGen/PowerPC/p8-scalar_vector_conversions.ll
+++ b/test/CodeGen/PowerPC/p8-scalar_vector_conversions.ll
@@ -328,7 +328,6 @@ entry:
 ; CHECK-LABEL: @getuc0
 ; CHECK: mfvsrd 3, 34
 ; CHECK: rldicl 3, 3, 8, 56
-; CHECK: clrldi   3, 3, 56
 ; CHECK-LE-LABEL: @getuc0
 ; CHECK-LE: mfvsrd 3,
 ; CHECK-LE: clrldi   3, 3, 56
@@ -342,11 +341,9 @@ entry:
 ; CHECK-LABEL: @getuc1
 ; CHECK: mfvsrd 3, 34
 ; CHECK: rldicl 3, 3, 16, 56
-; CHECK: clrldi   3, 3, 56
 ; CHECK-LE-LABEL: @getuc1
 ; CHECK-LE: mfvsrd 3,
 ; CHECK-LE: rldicl 3, 3, 56, 56
-; CHECK-LE: clrldi   3, 3, 56
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -357,11 +354,9 @@ entry:
 ; CHECK-LABEL: @getuc2
 ; CHECK: mfvsrd 3, 34
 ; CHECK: rldicl 3, 3, 24, 56
-; CHECK: clrldi   3, 3, 56
 ; CHECK-LE-LABEL: @getuc2
 ; CHECK-LE: mfvsrd 3,
 ; CHECK-LE: rldicl 3, 3, 48, 56
-; CHECK-LE: clrldi   3, 3, 56
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -372,11 +367,9 @@ entry:
 ; CHECK-LABEL: @getuc3
 ; CHECK: mfvsrd 3, 34
 ; CHECK: rldicl 3, 3, 32, 56
-; CHECK: clrldi   3, 3, 56
 ; CHECK-LE-LABEL: @getuc3
 ; CHECK-LE: mfvsrd 3,
 ; CHECK-LE: rldicl 3, 3, 40, 56
-; CHECK-LE: clrldi   3, 3, 56
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -387,11 +380,9 @@ entry:
 ; CHECK-LABEL: @getuc4
 ; CHECK: mfvsrd 3, 34
 ; CHECK: rldicl 3, 3, 40, 56
-; CHECK: clrldi   3, 3, 56
 ; CHECK-LE-LABEL: @getuc4
 ; CHECK-LE: mfvsrd 3,
 ; CHECK-LE: rldicl 3, 3, 32, 56
-; CHECK-LE: clrldi   3, 3, 56
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -402,11 +393,9 @@ entry:
 ; CHECK-LABEL: @getuc5
 ; CHECK: mfvsrd 3, 34
 ; CHECK: rldicl 3, 3, 48, 56
-; CHECK: clrldi   3, 3, 56
 ; CHECK-LE-LABEL: @getuc5
 ; CHECK-LE: mfvsrd 3,
 ; CHECK-LE: rldicl 3, 3, 24, 56
-; CHECK-LE: clrldi   3, 3, 56
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -417,11 +406,9 @@ entry:
 ; CHECK-LABEL: @getuc6
 ; CHECK: mfvsrd 3, 34
 ; CHECK: rldicl 3, 3, 56, 56
-; CHECK: clrldi   3, 3, 56
 ; CHECK-LE-LABEL: @getuc6
 ; CHECK-LE: mfvsrd 3,
 ; CHECK-LE: rldicl 3, 3, 16, 56
-; CHECK-LE: clrldi   3, 3, 56
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -435,7 +422,6 @@ entry:
 ; CHECK-LE-LABEL: @getuc7
 ; CHECK-LE: mfvsrd 3,
 ; CHECK-LE: rldicl 3, 3, 8, 56
-; CHECK-LE: clrldi   3, 3, 56
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -446,7 +432,6 @@ entry:
 ; CHECK-LABEL: @getuc8
 ; CHECK: mfvsrd 3,
 ; CHECK: rldicl 3, 3, 8, 56
-; CHECK: clrldi   3, 3, 56
 ; CHECK-LE-LABEL: @getuc8
 ; CHECK-LE: mfvsrd 3, 34
 ; CHECK-LE: clrldi   3, 3, 56
@@ -460,11 +445,9 @@ entry:
 ; CHECK-LABEL: @getuc9
 ; CHECK: mfvsrd 3,
 ; CHECK: rldicl 3, 3, 16, 56
-; CHECK: clrldi   3, 3, 56
 ; CHECK-LE-LABEL: @getuc9
 ; CHECK-LE: mfvsrd 3, 34
 ; CHECK-LE: rldicl 3, 3, 56, 56
-; CHECK-LE: clrldi   3, 3, 56
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -475,11 +458,9 @@ entry:
 ; CHECK-LABEL: @getuc10
 ; CHECK: mfvsrd 3,
 ; CHECK: rldicl 3, 3, 24, 56
-; CHECK: clrldi   3, 3, 56
 ; CHECK-LE-LABEL: @getuc10
 ; CHECK-LE: mfvsrd 3, 34
 ; CHECK-LE: rldicl 3, 3, 48, 56
-; CHECK-LE: clrldi   3, 3, 56
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -490,11 +471,9 @@ entry:
 ; CHECK-LABEL: @getuc11
 ; CHECK: mfvsrd 3,
 ; CHECK: rldicl 3, 3, 32, 56
-; CHECK: clrldi   3, 3, 56
 ; CHECK-LE-LABEL: @getuc11
 ; CHECK-LE: mfvsrd 3, 34
 ; CHECK-LE: rldicl 3, 3, 40, 56
-; CHECK-LE: clrldi   3, 3, 56
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -505,11 +484,9 @@ entry:
 ; CHECK-LABEL: @getuc12
 ; CHECK: mfvsrd 3,
 ; CHECK: rldicl 3, 3, 40, 56
-; CHECK: clrldi   3, 3, 56
 ; CHECK-LE-LABEL: @getuc12
 ; CHECK-LE: mfvsrd 3, 34
 ; CHECK-LE: rldicl 3, 3, 32, 56
-; CHECK-LE: clrldi   3, 3, 56
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -520,11 +497,9 @@ entry:
 ; CHECK-LABEL: @getuc13
 ; CHECK: mfvsrd 3,
 ; CHECK: rldicl 3, 3, 48, 56
-; CHECK: clrldi   3, 3, 56
 ; CHECK-LE-LABEL: @getuc13
 ; CHECK-LE: mfvsrd 3, 34
 ; CHECK-LE: rldicl 3, 3, 24, 56
-; CHECK-LE: clrldi   3, 3, 56
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -535,11 +510,9 @@ entry:
 ; CHECK-LABEL: @getuc14
 ; CHECK: mfvsrd 3,
 ; CHECK: rldicl 3, 3, 56, 56
-; CHECK: clrldi   3, 3, 56
 ; CHECK-LE-LABEL: @getuc14
 ; CHECK-LE: mfvsrd 3, 34
 ; CHECK-LE: rldicl 3, 3, 16, 56
-; CHECK-LE: clrldi   3, 3, 56
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -553,7 +526,6 @@ entry:
 ; CHECK-LE-LABEL: @getuc15
 ; CHECK-LE: mfvsrd 3, 34
 ; CHECK-LE: rldicl 3, 3, 8, 56
-; CHECK-LE: clrldi   3, 3, 56
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -739,7 +711,6 @@ entry:
 ; CHECK-LABEL: @getus0
 ; CHECK: mfvsrd 3, 34
 ; CHECK: rldicl 3, 3, 16, 48
-; CHECK: clrldi   3, 3, 48
 ; CHECK-LE-LABEL: @getus0
 ; CHECK-LE: mfvsrd 3,
 ; CHECK-LE: clrldi   3, 3, 48
@@ -753,11 +724,9 @@ entry:
 ; CHECK-LABEL: @getus1
 ; CHECK: mfvsrd 3, 34
 ; CHECK: rldicl 3, 3, 32, 48
-; CHECK: clrldi   3, 3, 48
 ; CHECK-LE-LABEL: @getus1
 ; CHECK-LE: mfvsrd 3,
 ; CHECK-LE: rldicl 3, 3, 48, 48
-; CHECK-LE: clrldi   3, 3, 48
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -768,11 +737,9 @@ entry:
 ; CHECK-LABEL: @getus2
 ; CHECK: mfvsrd 3, 34
 ; CHECK: rldicl 3, 3, 48, 48
-; CHECK: clrldi   3, 3, 48
 ; CHECK-LE-LABEL: @getus2
 ; CHECK-LE: mfvsrd 3,
 ; CHECK-LE: rldicl 3, 3, 32, 48
-; CHECK-LE: clrldi   3, 3, 48
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -786,7 +753,6 @@ entry:
 ; CHECK-LE-LABEL: @getus3
 ; CHECK-LE: mfvsrd 3,
 ; CHECK-LE: rldicl 3, 3, 16, 48
-; CHECK-LE: clrldi   3, 3, 48
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -797,7 +763,6 @@ entry:
 ; CHECK-LABEL: @getus4
 ; CHECK: mfvsrd 3,
 ; CHECK: rldicl 3, 3, 16, 48
-; CHECK: clrldi   3, 3, 48
 ; CHECK-LE-LABEL: @getus4
 ; CHECK-LE: mfvsrd 3, 34
 ; CHECK-LE: clrldi   3, 3, 48
@@ -811,11 +776,9 @@ entry:
 ; CHECK-LABEL: @getus5
 ; CHECK: mfvsrd 3,
 ; CHECK: rldicl 3, 3, 32, 48
-; CHECK: clrldi   3, 3, 48
 ; CHECK-LE-LABEL: @getus5
 ; CHECK-LE: mfvsrd 3, 34
 ; CHECK-LE: rldicl 3, 3, 48, 48
-; CHECK-LE: clrldi   3, 3, 48
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -826,11 +789,9 @@ entry:
 ; CHECK-LABEL: @getus6
 ; CHECK: mfvsrd 3,
 ; CHECK: rldicl 3, 3, 48, 48
-; CHECK: clrldi   3, 3, 48
 ; CHECK-LE-LABEL: @getus6
 ; CHECK-LE: mfvsrd 3, 34
 ; CHECK-LE: rldicl 3, 3, 32, 48
-; CHECK-LE: clrldi   3, 3, 48
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -844,7 +805,6 @@ entry:
 ; CHECK-LE-LABEL: @getus7
 ; CHECK-LE: mfvsrd 3, 34
 ; CHECK-LE: rldicl 3, 3, 16, 48
-; CHECK-LE: clrldi   3, 3, 48
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -973,11 +933,9 @@ entry:
 ; CHECK-LABEL: @getui0
 ; CHECK: xxsldwi [[SHL:[0-9]+]], 34, 34, 3
 ; CHECK: mfvsrwz 3, [[SHL]]
-; CHECK: clrldi   3, 3, 32
 ; CHECK-LE-LABEL: @getui0
 ; CHECK-LE: xxswapd [[SHL:[0-9]+]], 34
 ; CHECK-LE: mfvsrwz 3, [[SHL]]
-; CHECK-LE: clrldi   3, 3, 32
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -987,11 +945,9 @@ entry:
   ret i32 %vecext
 ; CHECK-LABEL: @getui1
 ; CHECK: mfvsrwz 3, 34
-; CHECK: clrldi   3, 3, 32
 ; CHECK-LE-LABEL: @getui1
 ; CHECK-LE: xxsldwi [[SHL:[0-9]+]], 34, 34, 1
 ; CHECK-LE: mfvsrwz 3, [[SHL]]
-; CHECK-LE: clrldi   3, 3, 32
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -1002,10 +958,8 @@ entry:
 ; CHECK-LABEL: @getui2
 ; CHECK: xxsldwi [[SHL:[0-9]+]], 34, 34, 1
 ; CHECK: mfvsrwz 3, [[SHL]]
-; CHECK: clrldi   3, 3, 32
 ; CHECK-LE-LABEL: @getui2
 ; CHECK-LE: mfvsrwz 3, 34
-; CHECK-LE: clrldi   3, 3, 32
 }
 
 ; Function Attrs: norecurse nounwind readnone
@@ -1016,11 +970,9 @@ entry:
 ; CHECK-LABEL: @getui3
 ; CHECK: xxswapd [[SHL:[0-9]+]], 34
 ; CHECK: mfvsrwz 3, [[SHL]]
-; CHECK: clrldi   3, 3, 32
 ; CHECK-LE-LABEL: @getui3
 ; CHECK-LE: xxsldwi [[SHL:[0-9]+]], 34, 34, 3
 ; CHECK-LE: mfvsrwz 3, [[SHL]]
-; CHECK-LE: clrldi   3, 3, 32
 }
 
 ; Function Attrs: norecurse nounwind readnone
diff --git a/test/CodeGen/PowerPC/ppc-ctr-dead-code.ll b/test/CodeGen/PowerPC/ppc-ctr-dead-code.ll
index 71755f722cb..2cfbb2d00df 100644
--- a/test/CodeGen/PowerPC/ppc-ctr-dead-code.ll
+++ b/test/CodeGen/PowerPC/ppc-ctr-dead-code.ll
@@ -31,7 +31,7 @@ cleanup:                                          ; preds = %for.body, %for.cond
 ; CHECK-LABEL: limit_loop
 ; CHECK: mtctr
 ; CHECK-NOT: addi {{[0-9]+}}, {{[0-9]+}}, 1
-; CHECK: bdnz
+; CHECK: bdzlr
 ; CHECK: blr
 }