[ARM GlobalISel] Legalize extensions to < 32 bits

Make it legal to extend from e.g. s1 to s8 or s16.

llvm-svn: 359766

2 files changed, 132 insertions, 10 deletions

diff --git a/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp b/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp
index 689a77a9d93..71971197afe 100644
--- a/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp
@@ -82,7 +82,7 @@ ARMLegalizerInfo::ARMLegalizerInfo(const ARMSubtarget &ST) {
   }
 
   getActionDefinitionsBuilder({G_SEXT, G_ZEXT, G_ANYEXT})
-      .legalForCartesianProduct({s32}, {s1, s8, s16});
+      .legalForCartesianProduct({s8, s16, s32}, {s1, s8, s16});
 
   getActionDefinitionsBuilder({G_ADD, G_SUB, G_MUL, G_AND, G_OR, G_XOR})
       .legalFor({s32})
diff --git a/llvm/test/CodeGen/ARM/GlobalISel/arm-legalize-exts.mir b/llvm/test/CodeGen/ARM/GlobalISel/arm-legalize-exts.mir
index 672b42671a1..6fa6f58e11a 100644
--- a/llvm/test/CodeGen/ARM/GlobalISel/arm-legalize-exts.mir
+++ b/llvm/test/CodeGen/ARM/GlobalISel/arm-legalize-exts.mir
@@ -1,13 +1,20 @@
 # RUN: llc -mtriple arm-- -run-pass=legalizer %s -o - | FileCheck %s
 # RUN: llc -mtriple thumb-- -mattr=+v6t2 -run-pass=legalizer %s -o - | FileCheck %s
 --- |
-  define void @test_zext_s16() { ret void }
-  define void @test_sext_s8() { ret void }
-  define void @test_anyext_s1() { ret void }
+  define void @test_zext_s16_to_s32() { ret void }
+  define void @test_sext_s8_to_s32() { ret void }
+  define void @test_anyext_s1_to_s32() { ret void }
+
+  define void @test_zext_s8_to_s16() { ret void }
+  define void @test_sext_s1_to_s16() { ret void }
+
+  define void @test_anyext_s1_to_s8() { ret void }
+
+  define void @test_ext_combine() { ret void }
 ...
 ---
-name:            test_zext_s16
-# CHECK-LABEL: name: test_zext_s16
+name:            test_zext_s16_to_s32
+# CHECK-LABEL: name: test_zext_s16_to_s32
 legalized:       false
 # CHECK: legalized: true
 regBankSelected: false
@@ -30,8 +37,8 @@ body:             |
     BX_RET 14, $noreg, implicit $r0
 ...
 ---
-name:            test_sext_s8
-# CHECK-LABEL: name: test_sext_s8
+name:            test_sext_s8_to_s32
+# CHECK-LABEL: name: test_sext_s8_to_s32
 legalized:       false
 # CHECK: legalized: true
 regBankSelected: false
@@ -54,8 +61,8 @@ body:             |
     BX_RET 14, $noreg, implicit $r0
 ...
 ---
-name:            test_anyext_s1
-# CHECK-LABEL: name: test_anyext_s1
+name:            test_anyext_s1_to_s32
+# CHECK-LABEL: name: test_anyext_s1_to_s32
 legalized:       false
 # CHECK: legalized: true
 regBankSelected: false
@@ -77,3 +84,118 @@ body:             |
     $r0 = COPY %2(s32)
     BX_RET 14, $noreg, implicit $r0
 ...
+---
+name:            test_zext_s8_to_s16
+# CHECK-LABEL: name: test_zext_s8_to_s16
+legalized:       false
+# CHECK: legalized: true
+regBankSelected: false
+selected:        false
+tracksRegLiveness: true
+registers:
+  - { id: 0, class: _ }
+  - { id: 1, class: _ }
+  - { id: 2, class: _ }
+body:             |
+  bb.0:
+    liveins: $r0
+
+    %0(p0) = COPY $r0
+    %1(s8) = G_LOAD %0(p0) :: (load 1)
+    %2(s16) = G_ZEXT %1
+    ; G_ZEXT from s8 to s16 is legal, so we should find it unchanged in the output
+    ; CHECK: {{%[0-9]+}}:_(s16) = G_ZEXT {{%[0-9]+}}(s8)
+    G_STORE %2(s16), %0(p0) :: (store 2)
+    BX_RET 14, $noreg
+...
+---
+name:            test_sext_s1_to_s16
+# CHECK-LABEL: name: test_sext_s1_to_s16
+legalized:       false
+# CHECK: legalized: true
+regBankSelected: false
+selected:        false
+tracksRegLiveness: true
+registers:
+  - { id: 0, class: _ }
+  - { id: 1, class: _ }
+  - { id: 2, class: _ }
+body:             |
+  bb.0:
+    liveins: $r0
+
+    %0(p0) = COPY $r0
+    %1(s1) = G_LOAD %0(p0) :: (load 1)
+    %2(s16) = G_SEXT %1(s1)
+    ; G_SEXT from s1 to s16 is legal, so we should find it unchanged in the output
+    ; CHECK: {{%[0-9]+}}:_(s16) = G_SEXT {{%[0-9]+}}(s1)
+    G_STORE %2(s16), %0(p0) :: (store 2)
+    BX_RET 14, $noreg
+...
+---
+name:            test_anyext_s1_to_s8
+# CHECK-LABEL: name: test_anyext_s1_to_s8
+legalized:       false
+# CHECK: legalized: true
+regBankSelected: false
+selected:        false
+tracksRegLiveness: true
+registers:
+  - { id: 0, class: _ }
+  - { id: 1, class: _ }
+  - { id: 2, class: _ }
+body:             |
+  bb.0:
+    liveins: $r0
+
+    %0(p0) = COPY $r0
+    %1(s1) = G_LOAD %0(p0) :: (load 1)
+    %2(s8) = G_ANYEXT %1
+    ; G_ANYEXT from s1 to s8 is legal, so we should find it unchanged in the output
+    ; CHECK: {{%[0-9]+}}:_(s8) = G_ANYEXT {{%[0-9]+}}(s1)
+    G_STORE %2(s8), %0(p0) :: (store 1)
+    BX_RET 14, $noreg
+...
+---
+name:            test_ext_combine
+# CHECK-LABEL: name: test_ext_combine
+legalized:       false
+# CHECK: legalized: true
+regBankSelected: false
+selected:        false
+tracksRegLiveness: true
+registers:
+  - { id: 0, class: _ }
+  - { id: 1, class: _ }
+  - { id: 2, class: _ }
+  - { id: 3, class: _ }
+  - { id: 4, class: _ }
+  - { id: 5, class: _ }
+body:             |
+  bb.0:
+    liveins: $r0
+
+    %0(p0) = COPY $r0
+    %1(s8) = G_LOAD %0(p0) :: (load 1)
+    ; CHECK: [[V8:%[0-9]+]]:_(s8) = G_LOAD
+
+    %2(s16) = G_ZEXT %1
+    %3(s16) = G_SEXT %1
+
+    %4(s16) = G_OR %2, %3
+    ; G_OR is going to widen to 32 bits and the extensions/truncs should combine
+    ; with the already existing ones
+    ; CHECK: [[ZEXT:%[0-9]+]]:_(s32) = G_ZEXT [[V8]](s8)
+    ; CHECK: [[SEXT:%[0-9]+]]:_(s32) = G_SEXT [[V8]](s8)
+    ; CHECK: [[OR:%[0-9]+]]:_(s32) = G_OR [[ZEXT]], [[SEXT]]
+    ; CHECK: [[BITS:%[0-9]+]]:_(s32) = G_CONSTANT i32 16
+    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY [[OR]]
+    ; CHECK: [[SHL:%[0-9]+]]:_(s32) = G_SHL [[COPY]], [[BITS]](s32)
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s32) = G_ASHR [[SHL]], [[BITS]](s32)
+    ; CHECK: $r0 = COPY [[ASHR]]
+
+    %5(s32) = G_SEXT %4(s16)
+    $r0 = COPY %5
+
+    BX_RET 14, $noreg, implicit $r0
+...